Merge branch 'worktree-slice-0.3-first-combat'

apps/api/src/app.module.ts

@@ -1,5 +1,6 @@
 import { Module } from '@nestjs/common';
 import { CharactersModule } from './characters/characters.module';
+import { CombatModule } from './combat/combat.module';
 import { DatabaseModule } from './database/database.module';
 import { HealthModule } from './health/health.module';
 import { HuntingModule } from './hunting/hunting.module';
@@ -14,6 +15,7 @@ import { WorldModule } from './world/world.module';
     TravelModule,
     WorldModule,
     HuntingModule,
+    CombatModule,
   ],
 })
 export class AppModule {}

apps/api/src/characters/character-combat-stats.service.spec.ts

@@ -0,0 +1,16 @@
+import { CharacterCombatStatsService } from './character-combat-stats.service';
+import { Character } from './entities/character.entity';
+
+describe('CharacterCombatStatsService', () => {
+  it('derives combat stats from the character, with a temporary fixed weapon/armor stand-in', () => {
+    const service = new CharacterCombatStatsService();
+    const character = { baseHp: 100, baseAttack: 6 } as Character;
+
+    expect(service.getStats(character)).toEqual({
+      maxHp: 100,
+      attack: 6,
+      weaponDamage: 8,
+      armor: 6,
+    });
+  });
+});

apps/api/src/characters/character-combat-stats.service.ts

@@ -0,0 +1,28 @@
+import { Injectable } from '@nestjs/common';
+import { Character } from './entities/character.entity';
+
+export interface CharacterCombatStats {
+  maxHp: number;
+  attack: number;
+  weaponDamage: number;
+  armor: number;
+}
+
+// TEMPORARY (Slice 0.3): there is no equipment system yet. These constants
+// stand in for the starting weapon/armor until Slice 0.5 introduces real
+// equipment. Replacing them there must not change this method's signature
+// or the combat API it feeds (spec §10).
+const TEMPORARY_WEAPON_DAMAGE = 8;
+const TEMPORARY_ARMOR = 6;
+
+@Injectable()
+export class CharacterCombatStatsService {
+  getStats(character: Character): CharacterCombatStats {
+    return {
+      maxHp: character.baseHp,
+      attack: character.baseAttack,
+      weaponDamage: TEMPORARY_WEAPON_DAMAGE,
+      armor: TEMPORARY_ARMOR,
+    };
+  }
+}

apps/api/src/characters/characters.module.ts

@@ -1,5 +1,6 @@
 import { Module } from '@nestjs/common';
 import { TypeOrmModule } from '@nestjs/typeorm';
+import { CharacterCombatStatsService } from './character-combat-stats.service';
 import { CharactersController } from './characters.controller';
 import { CharactersService } from './characters.service';
 import { Character } from './entities/character.entity';
@@ -7,6 +8,7 @@ import { Character } from './entities/character.entity';
 @Module({
   imports: [TypeOrmModule.forFeature([Character])],
   controllers: [CharactersController],
-  providers: [CharactersService],
+  providers: [CharactersService, CharacterCombatStatsService],
+  exports: [CharacterCombatStatsService],
 })
 export class CharactersModule {}

apps/api/src/combat/combat-action.enum.ts

@@ -0,0 +1,6 @@
+// Only ATTACK is implemented in Slice 0.3. Future slices add HEAVY_STRIKE,
+// SHIELD_BASH, DEFEND, POTION, FLEE as real members with their own
+// CombatEngineService cases — do not add them here until their behavior ships.
+export enum CombatAction {
+  ATTACK = 'ATTACK',
+}

apps/api/src/combat/combat-damage.spec.ts

@@ -0,0 +1,17 @@
+import { calculateDamage } from './combat-damage';
+
+describe('calculateDamage', () => {
+  it('applies the established armor mitigation formula', () => {
+    // raw = 12 + 15 = 27; 27 * 60 / (60 + 20) = 20.25 -> rounds to 20
+    expect(calculateDamage({ attack: 12, weaponDamage: 15 }, 20)).toBe(20);
+  });
+
+  it('never returns less than 1 damage, even against extreme armor', () => {
+    expect(calculateDamage({ attack: 1, weaponDamage: 0 }, 100_000)).toBe(1);
+  });
+
+  it('treats an attacker with no weaponDamage as having attack alone as its raw damage', () => {
+    // raw = 9; 9 * 60 / (60 + 5) = 8.307... -> rounds to 8
+    expect(calculateDamage({ attack: 9 }, 5)).toBe(8);
+  });
+});

apps/api/src/combat/combat-damage.ts

@@ -0,0 +1,13 @@
+export interface DamageAttacker {
+  attack: number;
+  weaponDamage?: number;
+}
+
+const ARMOR_MITIGATION_CONSTANT = 60;
+
+export function calculateDamage(attacker: DamageAttacker, targetArmor: number): number {
+  const rawDamage = attacker.attack + (attacker.weaponDamage ?? 0);
+  const mitigatedDamage =
+    (rawDamage * ARMOR_MITIGATION_CONSTANT) / (ARMOR_MITIGATION_CONSTANT + targetArmor);
+  return Math.max(1, Math.round(mitigatedDamage));
+}

apps/api/src/combat/combat-engine.service.spec.ts

@@ -0,0 +1,107 @@
+import { CombatAction } from './combat-action.enum';
+import { CombatEngineService, UnsupportedCombatActionError } from './combat-engine.service';
+import { CombatEngineState } from './combat-engine.types';
+import { CombatEventType } from './combat-event-type.enum';
+import { CombatStatus } from './combat-status.enum';
+import { Combatant } from './combatant.enum';
+
+function baseState(overrides: Partial<CombatEngineState> = {}): CombatEngineState {
+  return {
+    status: CombatStatus.ACTIVE,
+    round: 1,
+    player: {
+      currentHp: 100,
+      maxHp: 100,
+      stats: { attack: 6, weaponDamage: 8, armor: 6 },
+    },
+    monster: {
+      currentHp: 45,
+      maxHp: 45,
+      stats: { attack: 5, armor: 0 },
+    },
+    ...overrides,
+  };
+}
+
+describe('CombatEngineService', () => {
+  let engine: CombatEngineService;
+
+  beforeEach(() => {
+    engine = new CombatEngineService();
+  });
+
+  it('reduces monster HP by the calculated damage and emits a DAMAGE event', () => {
+    const result = engine.resolveAction(baseState(), { action: CombatAction.ATTACK });
+
+    // raw = 6 + 8 = 14; armor 0 -> 14 mitigated
+    expect(result.state.monster.currentHp).toBe(45 - 14);
+    expect(result.events[0]).toEqual({
+      source: Combatant.PLAYER,
+      target: Combatant.MONSTER,
+      type: CombatEventType.DAMAGE,
+      amount: 14,
+    });
+  });
+
+  it('lets the monster retaliate when it survives the player attack, and advances the round', () => {
+    const result = engine.resolveAction(baseState(), { action: CombatAction.ATTACK });
+
+    // raw = 5; armor 6 -> 5*60/66 = 4.545 -> rounds to 5
+    expect(result.state.player.currentHp).toBe(100 - 5);
+    expect(result.events[1]).toEqual({
+      source: Combatant.MONSTER,
+      target: Combatant.PLAYER,
+      type: CombatEventType.DAMAGE,
+      amount: 5,
+    });
+    expect(result.state.status).toBe(CombatStatus.ACTIVE);
+    expect(result.state.round).toBe(2);
+  });
+
+  it('does not let the monster attack once it is reduced to 0 HP, and ends the combat as WON', () => {
+    const state = baseState({
+      monster: { currentHp: 10, maxHp: 45, stats: { attack: 5, armor: 0 } },
+    });
+
+    const result = engine.resolveAction(state, { action: CombatAction.ATTACK });
+
+    expect(result.state.monster.currentHp).toBe(0);
+    expect(result.state.status).toBe(CombatStatus.WON);
+    expect(result.state.round).toBe(1);
+    expect(result.events).toEqual([
+      { source: Combatant.PLAYER, target: Combatant.MONSTER, type: CombatEventType.DAMAGE, amount: 14 },
+      { source: Combatant.PLAYER, target: Combatant.MONSTER, type: CombatEventType.COMBAT_WON },
+    ]);
+  });
+
+  it('ends the combat as LOST when the monster attack reduces the player to 0 HP', () => {
+    const state = baseState({
+      player: { currentHp: 3, maxHp: 100, stats: { attack: 6, weaponDamage: 8, armor: 6 } },
+    });
+
+    const result = engine.resolveAction(state, { action: CombatAction.ATTACK });
+
+    expect(result.state.player.currentHp).toBe(0);
+    expect(result.state.status).toBe(CombatStatus.LOST);
+    expect(result.events).toEqual([
+      { source: Combatant.PLAYER, target: Combatant.MONSTER, type: CombatEventType.DAMAGE, amount: 14 },
+      { source: Combatant.MONSTER, target: Combatant.PLAYER, type: CombatEventType.DAMAGE, amount: 5 },
+      { source: Combatant.MONSTER, target: Combatant.PLAYER, type: CombatEventType.COMBAT_LOST },
+    ]);
+  });
+
+  it('produces the exact same result for the same state and action (determinism)', () => {
+    const state = baseState();
+
+    const first = engine.resolveAction(state, { action: CombatAction.ATTACK });
+    const second = engine.resolveAction(state, { action: CombatAction.ATTACK });
+
+    expect(first).toEqual(second);
+  });
+
+  it('throws UnsupportedCombatActionError for an action it does not implement', () => {
+    expect(() =>
+      engine.resolveAction(baseState(), { action: 'HEAVY_STRIKE' as CombatAction }),
+    ).toThrow(UnsupportedCombatActionError);
+  });
+});

apps/api/src/combat/combat-engine.service.ts

@@ -0,0 +1,83 @@
+import { Injectable } from '@nestjs/common';
+import { CombatAction } from './combat-action.enum';
+import { calculateDamage } from './combat-damage';
+import { Combatant } from './combatant.enum';
+import {
+  CombatActionInput,
+  CombatEngineEvent,
+  CombatEngineResult,
+  CombatEngineState,
+} from './combat-engine.types';
+import { CombatEventType } from './combat-event-type.enum';
+import { CombatStatus } from './combat-status.enum';
+
+export class UnsupportedCombatActionError extends Error {
+  constructor(action: string) {
+    super(`Unsupported combat action: ${action}`);
+  }
+}
+
+@Injectable()
+export class CombatEngineService {
+  resolveAction(state: CombatEngineState, input: CombatActionInput): CombatEngineResult {
+    switch (input.action) {
+      case CombatAction.ATTACK:
+        return this.resolveAttack(state);
+      default:
+        throw new UnsupportedCombatActionError(input.action);
+    }
+  }
+
+  private resolveAttack(state: CombatEngineState): CombatEngineResult {
+    const events: CombatEngineEvent[] = [];
+    const player = { ...state.player };
+    const monster = { ...state.monster };
+
+    const playerDamage = calculateDamage(player.stats, monster.stats.armor);
+    monster.currentHp = Math.max(0, monster.currentHp - playerDamage);
+    events.push({
+      source: Combatant.PLAYER,
+      target: Combatant.MONSTER,
+      type: CombatEventType.DAMAGE,
+      amount: playerDamage,
+    });
+
+    if (monster.currentHp <= 0) {
+      events.push({
+        source: Combatant.PLAYER,
+        target: Combatant.MONSTER,
+        type: CombatEventType.COMBAT_WON,
+      });
+      return {
+        state: { ...state, player, monster, status: CombatStatus.WON },
+        events,
+      };
+    }
+
+    const monsterDamage = calculateDamage(monster.stats, player.stats.armor);
+    player.currentHp = Math.max(0, player.currentHp - monsterDamage);
+    events.push({
+      source: Combatant.MONSTER,
+      target: Combatant.PLAYER,
+      type: CombatEventType.DAMAGE,
+      amount: monsterDamage,
+    });
+
+    if (player.currentHp <= 0) {
+      events.push({
+        source: Combatant.MONSTER,
+        target: Combatant.PLAYER,
+        type: CombatEventType.COMBAT_LOST,
+      });
+      return {
+        state: { ...state, player, monster, status: CombatStatus.LOST },
+        events,
+      };
+    }
+
+    return {
+      state: { ...state, player, monster, status: CombatStatus.ACTIVE, round: state.round + 1 },
+      events,
+    };
+  }
+}

apps/api/src/combat/combat-engine.types.ts

@@ -0,0 +1,39 @@
+import { Combatant } from './combatant.enum';
+import { CombatAction } from './combat-action.enum';
+import { CombatEventType } from './combat-event-type.enum';
+import { CombatStatus } from './combat-status.enum';
+
+export interface CombatEngineCombatantStats {
+  attack: number;
+  weaponDamage?: number;
+  armor: number;
+}
+
+export interface CombatEngineCombatant {
+  currentHp: number;
+  maxHp: number;
+  stats: CombatEngineCombatantStats;
+}
+
+export interface CombatEngineState {
+  status: CombatStatus;
+  round: number;
+  player: CombatEngineCombatant;
+  monster: CombatEngineCombatant;
+}
+
+export interface CombatActionInput {
+  action: CombatAction;
+}
+
+export interface CombatEngineEvent {
+  source: Combatant;
+  target: Combatant;
+  type: CombatEventType;
+  amount?: number;
+}
+
+export interface CombatEngineResult {
+  state: CombatEngineState;
+  events: CombatEngineEvent[];
+}

apps/api/src/combat/combat-event-type.enum.ts

@@ -0,0 +1,5 @@
+export enum CombatEventType {
+  DAMAGE = 'DAMAGE',
+  COMBAT_WON = 'COMBAT_WON',
+  COMBAT_LOST = 'COMBAT_LOST',
+}

apps/api/src/combat/combat-status.enum.ts

@@ -0,0 +1,5 @@
+export enum CombatStatus {
+  ACTIVE = 'ACTIVE',
+  WON = 'WON',
+  LOST = 'LOST',
+}

apps/api/src/combat/combat.controller.spec.ts

@@ -0,0 +1,72 @@
+import { INestApplication } from '@nestjs/common';
+import { Test } from '@nestjs/testing';
+import request from 'supertest';
+import { App } from 'supertest/types';
+import { configureApplication } from '../app.config';
+import { DEMO_CHARACTER_ID } from '../demo/demo-character.constants';
+import { CombatController } from './combat.controller';
+import { CombatService } from './combat.service';
+
+describe('CombatController', () => {
+  let app: INestApplication<App>;
+  const getCombat = jest.fn();
+  const performAction = jest.fn();
+
+  beforeEach(async () => {
+    getCombat.mockReset();
+    performAction.mockReset();
+    const module = await Test.createTestingModule({
+      controllers: [CombatController],
+      providers: [{ provide: CombatService, useValue: { getCombat, performAction } }],
+    }).compile();
+
+    app = module.createNestApplication<App>();
+    configureApplication(app);
+    await app.init();
+  });
+
+  afterEach(async () => {
+    await app.close();
+  });
+
+  it('delegates GET /api/combats/:combatId to combatService.getCombat', async () => {
+    const combat = { id: 'combat-1', status: 'ACTIVE', round: 1, player: {}, monster: {}, events: [] };
+    getCombat.mockResolvedValue(combat);
+
+    const response = await request(app.getHttpServer()).get('/api/combats/combat-1').expect(200);
+
+    expect(getCombat).toHaveBeenCalledWith(DEMO_CHARACTER_ID, 'combat-1');
+    expect(response.body).toEqual(combat);
+  });
+
+  it('delegates POST /api/combats/:combatId/actions with only the action field', async () => {
+    const combat = { id: 'combat-1', status: 'ACTIVE', round: 2, player: {}, monster: {}, events: [] };
+    performAction.mockResolvedValue(combat);
+
+    const response = await request(app.getHttpServer())
+      .post('/api/combats/combat-1/actions')
+      .send({ action: 'ATTACK' })
+      .expect(201);
+
+    expect(performAction).toHaveBeenCalledWith(DEMO_CHARACTER_ID, 'combat-1', 'ATTACK');
+    expect(response.body).toEqual(combat);
+  });
+
+  it('rejects an unknown action value', async () => {
+    await request(app.getHttpServer())
+      .post('/api/combats/combat-1/actions')
+      .send({ action: 'HEAVY_STRIKE' })
+      .expect(400);
+
+    expect(performAction).not.toHaveBeenCalled();
+  });
+
+  it('rejects server-owned combat fields the client must never send', async () => {
+    await request(app.getHttpServer())
+      .post('/api/combats/combat-1/actions')
+      .send({ action: 'ATTACK', damage: 999, playerHp: 1, monsterHp: 1, round: 99 })
+      .expect(400);
+
+    expect(performAction).not.toHaveBeenCalled();
+  });
+});

apps/api/src/combat/combat.controller.ts

@@ -0,0 +1,19 @@
+import { Body, Controller, Get, Param, Post } from '@nestjs/common';
+import { DEMO_CHARACTER_ID } from '../demo/demo-character.constants';
+import { CombatActionDto } from './dto/combat-action.dto';
+import { CombatService } from './combat.service';
+
+@Controller('combats')
+export class CombatController {
+  constructor(private readonly combatService: CombatService) {}
+
+  @Get(':combatId')
+  getCombat(@Param('combatId') combatId: string) {
+    return this.combatService.getCombat(DEMO_CHARACTER_ID, combatId);
+  }
+
+  @Post(':combatId/actions')
+  performAction(@Param('combatId') combatId: string, @Body() dto: CombatActionDto) {
+    return this.combatService.performAction(DEMO_CHARACTER_ID, combatId, dto.action);
+  }
+}

apps/api/src/combat/combat.errors.ts

@@ -0,0 +1,87 @@
+import { HttpException, HttpStatus } from '@nestjs/common';
+
+export type CombatErrorCode =
+  | 'HUNT_ENCOUNTER_NOT_FOUND'
+  | 'HUNT_ENCOUNTER_ALREADY_CONSUMED'
+  | 'INVALID_HUNT_ENCOUNTER'
+  | 'CHARACTER_TRAVELLING'
+  | 'COMBAT_ALREADY_ACTIVE'
+  | 'COMBAT_NOT_FOUND'
+  | 'COMBAT_ALREADY_FINISHED'
+  | 'COMBAT_STATE_INVALID';
+
+export class CombatDomainError extends HttpException {
+  constructor(
+    public readonly code: CombatErrorCode,
+    status: HttpStatus,
+    message: string,
+  ) {
+    super({ statusCode: status, code, message }, status);
+  }
+}
+
+export function huntEncounterNotFound(): CombatDomainError {
+  return new CombatDomainError(
+    'HUNT_ENCOUNTER_NOT_FOUND',
+    HttpStatus.NOT_FOUND,
+    'This encounter could not be found.',
+  );
+}
+
+export function huntEncounterAlreadyConsumed(): CombatDomainError {
+  return new CombatDomainError(
+    'HUNT_ENCOUNTER_ALREADY_CONSUMED',
+    HttpStatus.CONFLICT,
+    'This encounter has already been used to start a combat.',
+  );
+}
+
+export function invalidHuntEncounter(): CombatDomainError {
+  return new CombatDomainError(
+    'INVALID_HUNT_ENCOUNTER',
+    HttpStatus.BAD_REQUEST,
+    'This encounter is not valid for the current character.',
+  );
+}
+
+export function characterTravelling(): CombatDomainError {
+  return new CombatDomainError(
+    'CHARACTER_TRAVELLING',
+    HttpStatus.CONFLICT,
+    'The character cannot fight while travelling.',
+  );
+}
+
+export function combatAlreadyActive(): CombatDomainError {
+  return new CombatDomainError(
+    'COMBAT_ALREADY_ACTIVE',
+    HttpStatus.CONFLICT,
+    'The character already has an active combat.',
+  );
+}
+
+export function combatNotFound(): CombatDomainError {
+  return new CombatDomainError(
+    'COMBAT_NOT_FOUND',
+    HttpStatus.NOT_FOUND,
+    'This combat could not be found.',
+  );
+}
+
+export function combatAlreadyFinished(): CombatDomainError {
+  return new CombatDomainError(
+    'COMBAT_ALREADY_FINISHED',
+    HttpStatus.CONFLICT,
+    'This combat has already finished.',
+  );
+}
+
+export function combatStateInvalid(): CombatDomainError {
+  return new CombatDomainError(
+    'COMBAT_STATE_INVALID',
+    HttpStatus.INTERNAL_SERVER_ERROR,
+    'The persisted combat references unavailable data.',
+  );
+}
+
+export { characterNotFound } from '../travel/travel.errors';

apps/api/src/combat/combat.module.ts

@@ -0,0 +1,25 @@
+import { Module } from '@nestjs/common';
+import { TypeOrmModule } from '@nestjs/typeorm';
+import { CharactersModule } from '../characters/characters.module';
+import { Character } from '../characters/entities/character.entity';
+import { Hunt } from '../hunting/entities/hunt.entity';
+import { HuntEncounter } from '../hunting/entities/hunt-encounter.entity';
+import { MonsterDefinition } from '../monsters/entities/monster-definition.entity';
+import { TravelModule } from '../travel/travel.module';
+import { CombatEngineService } from './combat-engine.service';
+import { CombatController } from './combat.controller';
+import { CombatService } from './combat.service';
+import { Combat } from './entities/combat.entity';
+import { CombatEvent } from './entities/combat-event.entity';
+import { HuntEncounterAttackController } from './hunt-encounter-attack.controller';
+
+@Module({
+  imports: [
+    TypeOrmModule.forFeature([Character, Hunt, HuntEncounter, MonsterDefinition, Combat, CombatEvent]),
+    TravelModule,
+    CharactersModule,
+  ],
+  controllers: [CombatController, HuntEncounterAttackController],
+  providers: [CombatService, CombatEngineService],
+})
+export class CombatModule {}

apps/api/src/combat/combat.service.spec.ts

@@ -0,0 +1,614 @@
+import { DataSource, EntityManager, EntityTarget } from 'typeorm';
+import { CharacterCombatStatsService } from '../characters/character-combat-stats.service';
+import { Character } from '../characters/entities/character.entity';
+import { Hunt } from '../hunting/entities/hunt.entity';
+import { HuntEncounter } from '../hunting/entities/hunt-encounter.entity';
+import { HuntStatus } from '../hunting/hunt-status.enum';
+import { MonsterDefinition } from '../monsters/entities/monster-definition.entity';
+import { TravelService } from '../travel/travel.service';
+import { CombatAction } from './combat-action.enum';
+import { CombatEngineService } from './combat-engine.service';
+import { CombatDomainError } from './combat.errors';
+import { CombatService } from './combat.service';
+import { CombatStatus } from './combat-status.enum';
+import { CombatEvent } from './entities/combat-event.entity';
+import { Combat } from './entities/combat.entity';
+
+const CHARACTER_ID = '10000000-0000-4000-8000-000000000001';
+const OTHER_CHARACTER_ID = '10000000-0000-4000-8000-000000000002';
+const HUNT_ID = '20000000-0000-4000-8000-000000000001';
+const ENCOUNTER_ID = '30000000-0000-4000-8000-000000000001';
+const MONSTER_ID = '40000000-0000-4000-8000-000000000001';
+
+interface FakeState {
+  characters: Character[];
+  hunts: Hunt[];
+  huntEncounters: HuntEncounter[];
+  monsters: MonsterDefinition[];
+  combats: Combat[];
+  combatEvents: CombatEvent[];
+}
+
+class FakeRepository<T extends { id: string }> {
+  constructor(
+    private readonly state: FakeState,
+    private readonly target: EntityTarget<T>,
+    private readonly inTransaction: boolean,
+    private readonly dataSource: FakeDataSource,
+  ) {}
+
+  findOne(options: {
+    where: Partial<T>;
+    lock?: { mode: string };
+  }): Promise<T | null> {
+    if (options.lock) {
+      if (!this.inTransaction) {
+        throw new Error('Pessimistic locks require a transaction');
+      }
+      this.dataSource.locks.push({
+        target: this.target,
+        mode: options.lock.mode,
+      });
+    }
+    return Promise.resolve(
+      this.rows().find((row) => this.matches(row, options.where)) ?? null,
+    );
+  }
+
+  findOneBy(where: Partial<T>): Promise<T | null> {
+    return Promise.resolve(
+      this.rows().find((row) => this.matches(row, where)) ?? null,
+    );
+  }
+
+  find(options: {
+    where: Partial<T>;
+    order?: Partial<Record<keyof T, 'ASC' | 'DESC'>>;
+  }): Promise<T[]> {
+    const matched = this.rows().filter((row) =>
+      this.matches(row, options.where),
+    );
+    const orderKey = options.order
+      ? (Object.keys(options.order)[0] as keyof T)
+      : undefined;
+    if (orderKey) {
+      const direction = options.order![orderKey] === 'DESC' ? -1 : 1;
+      matched.sort((a, b) => {
+        if (a[orderKey] === b[orderKey]) return 0;
+        return a[orderKey] > b[orderKey] ? direction : -direction;
+      });
+    }
+    return Promise.resolve(matched);
+  }
+
+  count(options: { where: Partial<T> }): Promise<number> {
+    return Promise.resolve(
+      this.rows().filter((row) => this.matches(row, options.where)).length,
+    );
+  }
+
+  create(values: Partial<T>): T {
+    return { ...values } as T;
+  }
+
+  save(entity: T): Promise<T> {
+    if (!entity.id) {
+      entity.id = this.dataSource.nextId(this.targetName());
+    }
+    const rows = this.rows();
+    const index = rows.findIndex((row) => row.id === entity.id);
+    if (index === -1) {
+      rows.push(entity);
+    } else {
+      rows[index] = entity;
+    }
+    return Promise.resolve(entity);
+  }
+
+  private rows(): T[] {
+    if (this.target === Character) return this.state.characters as T[];
+    if (this.target === Hunt) return this.state.hunts as T[];
+    if (this.target === HuntEncounter) return this.state.huntEncounters as T[];
+    if (this.target === MonsterDefinition) return this.state.monsters as T[];
+    if (this.target === Combat) return this.state.combats as T[];
+    if (this.target === CombatEvent) return this.state.combatEvents as T[];
+    throw new Error(`Unsupported repository ${this.targetName()}`);
+  }
+
+  private matches(row: T, where: Partial<T>): boolean {
+    return Object.entries(where).every(
+      ([key, value]) => row[key as keyof T] === value,
+    );
+  }
+
+  private targetName(): string {
+    return typeof this.target === 'function'
+      ? this.target.name
+      : 'EntitySchema';
+  }
+}
+
+class FakeEntityManager {
+  constructor(
+    private readonly state: FakeState,
+    private readonly dataSource: FakeDataSource,
+  ) {}
+
+  getRepository<T extends { id: string }>(target: EntityTarget<T>) {
+    return new FakeRepository(this.state, target, true, this.dataSource);
+  }
+}
+
+class FakeDataSource {
+  readonly locks: Array<{ target: EntityTarget<unknown>; mode: string }> = [];
+  private readonly idCounters = new Map<string, number>();
+
+  constructor(public state: FakeState) {}
+
+  getRepository<T extends { id: string }>(target: EntityTarget<T>) {
+    return new FakeRepository(this.state, target, false, this);
+  }
+
+  async transaction<T>(
+    work: (manager: EntityManager) => Promise<T>,
+  ): Promise<T> {
+    const draft = structuredClone(this.state);
+    const result = await work(
+      new FakeEntityManager(draft, this) as unknown as EntityManager,
+    );
+    this.state = draft;
+    return result;
+  }
+
+  nextId(targetName: string): string {
+    const next = (this.idCounters.get(targetName) ?? 0) + 1;
+    this.idCounters.set(targetName, next);
+    return `${targetName.toLowerCase()}-generated-${next}`;
+  }
+}
+
+function character(overrides: Partial<Character> = {}): Character {
+  return {
+    id: CHARACTER_ID,
+    name: 'Aric Duskwalker',
+    level: 1,
+    experience: 0,
+    baseHp: 100,
+    baseAttack: 6,
+    currentHp: 100,
+    currentLocationId: 'location-1',
+    createdAt: new Date('2026-08-18T09:00:00.000Z'),
+    updatedAt: new Date('2026-08-18T09:00:00.000Z'),
+    ...overrides,
+  } as Character;
+}
+
+function monster(
+  overrides: Partial<MonsterDefinition> = {},
+): MonsterDefinition {
+  return {
+    id: MONSTER_ID,
+    key: 'ash-rat',
+    name: 'Aschenratte',
+    level: 1,
+    maxHp: 45,
+    attack: 5,
+    armor: 0,
+    experienceReward: 8,
+    silverMin: 4,
+    silverMax: 7,
+    artworkPath: '/images/monsters/ash-rat.png',
+    createdAt: new Date('2026-08-18T09:00:00.000Z'),
+    updatedAt: new Date('2026-08-18T09:00:00.000Z'),
+    ...overrides,
+  };
+}
+
+function hunt(overrides: Partial<Hunt> = {}): Hunt {
+  return {
+    id: HUNT_ID,
+    characterId: CHARACTER_ID,
+    locationId: 'location-1',
+    status: HuntStatus.ACTIVE,
+    createdAt: new Date('2026-08-18T09:00:00.000Z'),
+    ...overrides,
+  } as Hunt;
+}
+
+function huntEncounter(overrides: Partial<HuntEncounter> = {}): HuntEncounter {
+  return {
+    id: ENCOUNTER_ID,
+    huntId: HUNT_ID,
+    monsterDefinitionId: MONSTER_ID,
+    position: 0,
+    consumedAt: null,
+    createdAt: new Date('2026-08-18T09:00:00.000Z'),
+    ...overrides,
+  } as HuntEncounter;
+}
+
+function createState(overrides: Partial<FakeState> = {}): FakeState {
+  return {
+    characters: [character()],
+    hunts: [hunt()],
+    huntEncounters: [huntEncounter()],
+    monsters: [monster()],
+    combats: [],
+    combatEvents: [],
+    ...overrides,
+  };
+}
+
+function fakeTravelService(
+  status: 'IDLE' | 'TRAVELLING' = 'IDLE',
+): TravelService {
+  return {
+    completeTravelIfDue: jest.fn().mockResolvedValue({ status }),
+  } as unknown as TravelService;
+}
+
+function createService(
+  options: { state?: FakeState; travelService?: TravelService } = {},
+) {
+  const state = options.state ?? createState();
+  const dataSource = new FakeDataSource(state);
+  const travelService = options.travelService ?? fakeTravelService();
+  const combatEngine = new CombatEngineService();
+  const characterCombatStats = new CharacterCombatStatsService();
+  const service = new CombatService(
+    dataSource as unknown as DataSource,
+    travelService,
+    combatEngine,
+    characterCombatStats,
+  );
+  return { dataSource, service, travelService };
+}
+
+async function expectCombatDomainError(
+  promise: Promise<unknown>,
+  code: string,
+): Promise<void> {
+  let error: unknown;
+  try {
+    await promise;
+  } catch (cause) {
+    error = cause;
+  }
+  expect(error).toBeInstanceOf(CombatDomainError);
+  if (!(error instanceof CombatDomainError)) {
+    throw new Error('Expected CombatDomainError');
+  }
+  expect(error.code).toBe(code);
+}
+
+describe('CombatService', () => {
+  describe('startCombat', () => {
+    it('starts an ACTIVE combat with snapshotted stats and full HP', async () => {
+      const { dataSource, service } = createService();
+
+      const combat = await service.startCombat(CHARACTER_ID, ENCOUNTER_ID);
+
+      expect(combat.status).toBe('ACTIVE');
+      expect(combat.round).toBe(1);
+      expect(combat.player).toEqual({
+        name: 'Aric Duskwalker',
+        maxHp: 100,
+        currentHp: 100,
+      });
+      expect(combat.monster).toEqual({
+        key: 'ash-rat',
+        name: 'Aschenratte',
+        level: 1,
+        maxHp: 45,
+        currentHp: 45,
+        artworkPath: '/images/monsters/ash-rat.png',
+      });
+      expect(combat.events).toEqual([]);
+      expect(dataSource.state.combats).toHaveLength(1);
+      expect(dataSource.state.combats[0]).toMatchObject({
+        characterId: CHARACTER_ID,
+        huntEncounterId: ENCOUNTER_ID,
+        monsterDefinitionId: MONSTER_ID,
+        status: CombatStatus.ACTIVE,
+        playerState: { attack: 6, weaponDamage: 8, armor: 6 },
+        monsterState: { attack: 5, armor: 0 },
+      });
+    });
+
+    it('marks the encounter as consumed', async () => {
+      const { dataSource, service } = createService();
+
+      await service.startCombat(CHARACTER_ID, ENCOUNTER_ID);
+
+      expect(dataSource.state.huntEncounters[0].consumedAt).not.toBeNull();
+    });
+
+    it('rejects an unknown encounter id', async () => {
+      const { service } = createService();
+
+      await expectCombatDomainError(
+        service.startCombat(CHARACTER_ID, 'unknown-id'),
+        'HUNT_ENCOUNTER_NOT_FOUND',
+      );
+    });
+
+    it('rejects an already-consumed encounter, and does not create a second combat', async () => {
+      const state = createState({
+        huntEncounters: [
+          huntEncounter({ consumedAt: new Date('2026-08-18T09:05:00.000Z') }),
+        ],
+      });
+      const { dataSource, service } = createService({ state });
+
+      await expectCombatDomainError(
+        service.startCombat(CHARACTER_ID, ENCOUNTER_ID),
+        'HUNT_ENCOUNTER_ALREADY_CONSUMED',
+      );
+      expect(dataSource.state.combats).toHaveLength(0);
+    });
+
+    it('rejects an encounter belonging to a different character', async () => {
+      const state = createState({
+        characters: [character(), character({ id: OTHER_CHARACTER_ID })],
+      });
+      const { service } = createService({ state });
+
+      await expectCombatDomainError(
+        service.startCombat(OTHER_CHARACTER_ID, ENCOUNTER_ID),
+        'INVALID_HUNT_ENCOUNTER',
+      );
+    });
+
+    it('rejects an encounter whose hunt is no longer ACTIVE', async () => {
+      const state = createState({
+        hunts: [hunt({ status: HuntStatus.SUPERSEDED })],
+      });
+      const { service } = createService({ state });
+
+      await expectCombatDomainError(
+        service.startCombat(CHARACTER_ID, ENCOUNTER_ID),
+        'INVALID_HUNT_ENCOUNTER',
+      );
+    });
+
+    it('rejects starting combat while the character is travelling', async () => {
+      const { service } = createService({
+        travelService: fakeTravelService('TRAVELLING'),
+      });
+
+      await expectCombatDomainError(
+        service.startCombat(CHARACTER_ID, ENCOUNTER_ID),
+        'CHARACTER_TRAVELLING',
+      );
+    });
+
+    it('rejects starting a second combat while one is already ACTIVE', async () => {
+      const state = createState({
+        combats: [
+          {
+            id: 'combat-existing',
+            characterId: CHARACTER_ID,
+            huntEncounterId: 'other-encounter',
+            monsterDefinitionId: MONSTER_ID,
+            status: CombatStatus.ACTIVE,
+            round: 1,
+            playerMaxHp: 100,
+            playerCurrentHp: 100,
+            monsterMaxHp: 45,
+            monsterCurrentHp: 45,
+            playerState: { attack: 6, weaponDamage: 8, armor: 6 },
+            monsterState: { attack: 5, armor: 0 },
+            createdAt: new Date(),
+            updatedAt: new Date(),
+            completedAt: null,
+          } as Combat,
+        ],
+      });
+      const { service } = createService({ state });
+
+      await expectCombatDomainError(
+        service.startCombat(CHARACTER_ID, ENCOUNTER_ID),
+        'COMBAT_ALREADY_ACTIVE',
+      );
+    });
+
+    it('locks the character and the active-combat lookup', async () => {
+      const { dataSource, service } = createService();
+
+      await service.startCombat(CHARACTER_ID, ENCOUNTER_ID);
+
+      expect(dataSource.locks).toEqual(
+        expect.arrayContaining([
+          { target: Character, mode: 'pessimistic_write' },
+          { target: Combat, mode: 'pessimistic_write' },
+        ]),
+      );
+    });
+  });
+
+  describe('performAction', () => {
+    async function startedCombat(state = createState()) {
+      const context = createService({ state });
+      const combat = await context.service.startCombat(
+        CHARACTER_ID,
+        ENCOUNTER_ID,
+      );
+      return { ...context, combatId: combat.id };
+    }
+
+    it('resolves ATTACK, persists HP/round changes, and returns them', async () => {
+      const { dataSource, service, combatId } = await startedCombat();
+
+      const result = await service.performAction(
+        CHARACTER_ID,
+        combatId,
+        CombatAction.ATTACK,
+      );
+
+      expect(result.status).toBe('ACTIVE');
+      expect(result.round).toBe(2);
+      expect(result.monster.currentHp).toBe(45 - 14);
+      expect(result.player.currentHp).toBe(100 - 5);
+      expect(dataSource.state.combats[0].round).toBe(2);
+      expect(dataSource.state.combats[0].monsterCurrentHp).toBe(31);
+      expect(dataSource.state.combats[0].playerCurrentHp).toBe(95);
+    });
+
+    it('persists ordered, sequential CombatEvents across multiple rounds', async () => {
+      const { dataSource, service, combatId } = await startedCombat();
+
+      await service.performAction(CHARACTER_ID, combatId, CombatAction.ATTACK);
+      await service.performAction(CHARACTER_ID, combatId, CombatAction.ATTACK);
+
+      const events = dataSource.state.combatEvents
+        .filter((event) => event.combatId === combatId)
+        .sort((a, b) => a.sequence - b.sequence);
+      expect(events.map((event) => event.sequence)).toEqual([1, 2, 3, 4]);
+      expect(events.map((event) => event.round)).toEqual([1, 1, 2, 2]);
+      expect(events[0]).toMatchObject({
+        source: 'PLAYER',
+        target: 'MONSTER',
+        type: 'DAMAGE',
+        amount: 14,
+      });
+      expect(events[1]).toMatchObject({
+        source: 'MONSTER',
+        target: 'PLAYER',
+        type: 'DAMAGE',
+        amount: 5,
+      });
+    });
+
+    it('ends the combat as WON, stops persisting new rounds, and rejects further actions', async () => {
+      const state = createState({ monsters: [monster({ maxHp: 10 })] });
+      const { dataSource, service, combatId } = await startedCombat(state);
+
+      const result = await service.performAction(
+        CHARACTER_ID,
+        combatId,
+        CombatAction.ATTACK,
+      );
+
+      expect(result.status).toBe('WON');
+      expect(dataSource.state.combats[0].completedAt).not.toBeNull();
+      await expectCombatDomainError(
+        service.performAction(CHARACTER_ID, combatId, CombatAction.ATTACK),
+        'COMBAT_ALREADY_FINISHED',
+      );
+    });
+
+    it('ends the combat as LOST, stops persisting new rounds, and rejects further actions', async () => {
+      const state = createState({
+        characters: [character({ baseHp: 1 })],
+      });
+      const { dataSource, service, combatId } = await startedCombat(state);
+
+      const result = await service.performAction(
+        CHARACTER_ID,
+        combatId,
+        CombatAction.ATTACK,
+      );
+
+      expect(result.status).toBe('LOST');
+      expect(dataSource.state.combats[0].status).toBe(CombatStatus.LOST);
+      expect(dataSource.state.combats[0].completedAt).not.toBeNull();
+      await expectCombatDomainError(
+        service.performAction(CHARACTER_ID, combatId, CombatAction.ATTACK),
+        'COMBAT_ALREADY_FINISHED',
+      );
+    });
+
+    it('rejects actions on an unknown combat id', async () => {
+      const { service } = createService();
+
+      await expectCombatDomainError(
+        service.performAction(
+          CHARACTER_ID,
+          'unknown-combat',
+          CombatAction.ATTACK,
+        ),
+        'COMBAT_NOT_FOUND',
+      );
+    });
+
+    it('rejects actions from a character who does not own the combat', async () => {
+      const { service, combatId } = await startedCombat();
+
+      await expectCombatDomainError(
+        service.performAction(
+          OTHER_CHARACTER_ID,
+          combatId,
+          CombatAction.ATTACK,
+        ),
+        'COMBAT_NOT_FOUND',
+      );
+    });
+
+    it('locks the combat row for the duration of the action', async () => {
+      const { dataSource, service, combatId } = await startedCombat();
+
+      await service.performAction(CHARACTER_ID, combatId, CombatAction.ATTACK);
+
+      expect(dataSource.locks).toEqual(
+        expect.arrayContaining([{ target: Combat, mode: 'pessimistic_write' }]),
+      );
+    });
+  });
+
+  describe('getCombat', () => {
+    it('returns the persisted state and ordered events after a refresh', async () => {
+      const context = createService();
+      const started = await context.service.startCombat(
+        CHARACTER_ID,
+        ENCOUNTER_ID,
+      );
+      await context.service.performAction(
+        CHARACTER_ID,
+        started.id,
+        CombatAction.ATTACK,
+      );
+
+      const reloaded = await context.service.getCombat(
+        CHARACTER_ID,
+        started.id,
+      );
+
+      expect(reloaded.round).toBe(2);
+      expect(reloaded.monster.currentHp).toBe(31);
+      expect(reloaded.events.map((event) => event.sequence)).toEqual([1, 2]);
+    });
+
+    it('rejects an unknown combat id', async () => {
+      const { service } = createService();
+
+      await expectCombatDomainError(
+        service.getCombat(CHARACTER_ID, 'unknown'),
+        'COMBAT_NOT_FOUND',
+      );
+    });
+
+    it('keeps returning LOST after the combat has ended', async () => {
+      const state = createState({
+        characters: [character({ baseHp: 1 })],
+      });
+      const context = createService({ state });
+      const started = await context.service.startCombat(
+        CHARACTER_ID,
+        ENCOUNTER_ID,
+      );
+      await context.service.performAction(
+        CHARACTER_ID,
+        started.id,
+        CombatAction.ATTACK,
+      );
+
+      const reloaded = await context.service.getCombat(
+        CHARACTER_ID,
+        started.id,
+      );
+
+      expect(reloaded.status).toBe('LOST');
+      expect(reloaded.player.currentHp).toBe(0);
+    });
+  });
+});

apps/api/src/combat/combat.service.ts

@@ -0,0 +1,339 @@
+import { Injectable } from '@nestjs/common';
+import { DataSource, Repository } from 'typeorm';
+import { CharacterCombatStatsService } from '../characters/character-combat-stats.service';
+import { Character } from '../characters/entities/character.entity';
+import { Hunt } from '../hunting/entities/hunt.entity';
+import { HuntEncounter } from '../hunting/entities/hunt-encounter.entity';
+import { HuntStatus } from '../hunting/hunt-status.enum';
+import { MonsterDefinition } from '../monsters/entities/monster-definition.entity';
+import { TravelService } from '../travel/travel.service';
+import { TravelStatus } from '../travel/travel-status.enum';
+import { CombatAction } from './combat-action.enum';
+import { CombatEngineService } from './combat-engine.service';
+import { CombatEngineState } from './combat-engine.types';
+import {
+  characterNotFound,
+  characterTravelling,
+  combatAlreadyActive,
+  combatAlreadyFinished,
+  combatNotFound,
+  combatStateInvalid,
+  huntEncounterAlreadyConsumed,
+  huntEncounterNotFound,
+  invalidHuntEncounter,
+} from './combat.errors';
+import { CombatStatus } from './combat-status.enum';
+import { CombatEvent } from './entities/combat-event.entity';
+import { Combat } from './entities/combat.entity';
+
+export interface CombatPlayerDto {
+  name: string;
+  maxHp: number;
+  currentHp: number;
+}
+
+export interface CombatMonsterDto {
+  key: string;
+  name: string;
+  level: number;
+  maxHp: number;
+  currentHp: number;
+  artworkPath: string;
+}
+
+export interface CombatEventDto {
+  round: number;
+  sequence: number;
+  type: string;
+  source: string;
+  target: string;
+  amount?: number;
+}
+
+export interface CombatDto {
+  id: string;
+  status: CombatStatus;
+  round: number;
+  player: CombatPlayerDto;
+  monster: CombatMonsterDto;
+  events: CombatEventDto[];
+}
+
+@Injectable()
+export class CombatService {
+  constructor(
+    private readonly dataSource: DataSource,
+    private readonly travelService: TravelService,
+    private readonly combatEngine: CombatEngineService,
+    private readonly characterCombatStats: CharacterCombatStatsService,
+  ) {}
+
+  async startCombat(
+    characterId: string,
+    encounterId: string,
+  ): Promise<CombatDto> {
+    const travel = await this.travelService.completeTravelIfDue(characterId);
+    if (travel.status === TravelStatus.TRAVELLING) {
+      throw characterTravelling();
+    }
+
+    return this.dataSource.transaction(async (manager) => {
+      const characters = manager.getRepository(Character);
+      const encounters = manager.getRepository(HuntEncounter);
+      const hunts = manager.getRepository(Hunt);
+      const monsters = manager.getRepository(MonsterDefinition);
+      const combats = manager.getRepository(Combat);
+
+      const character = await this.lockCharacter(characters, characterId);
+
+      const encounter = await encounters.findOne({
+        where: { id: encounterId },
+        lock: { mode: 'pessimistic_write' },
+      });
+      if (!encounter) {
+        throw huntEncounterNotFound();
+      }
+      if (encounter.consumedAt) {
+        throw huntEncounterAlreadyConsumed();
+      }
+
+      const hunt = await hunts.findOneBy({ id: encounter.huntId });
+      if (
+        !hunt ||
+        hunt.characterId !== characterId ||
+        hunt.status !== HuntStatus.ACTIVE
+      ) {
+        throw invalidHuntEncounter();
+      }
+
+      const existingActiveCombat = await combats.findOne({
+        where: { characterId, status: CombatStatus.ACTIVE },
+        lock: { mode: 'pessimistic_write' },
+      });
+      if (existingActiveCombat) {
+        throw combatAlreadyActive();
+      }
+
+      const monster = await monsters.findOneBy({
+        id: encounter.monsterDefinitionId,
+      });
+      if (!monster) {
+        throw invalidHuntEncounter();
+      }
+
+      const playerStats = this.characterCombatStats.getStats(character);
+
+      const combat = combats.create({
+        characterId,
+        huntEncounterId: encounter.id,
+        monsterDefinitionId: monster.id,
+        status: CombatStatus.ACTIVE,
+        round: 1,
+        playerMaxHp: playerStats.maxHp,
+        playerCurrentHp: playerStats.maxHp,
+        monsterMaxHp: monster.maxHp,
+        monsterCurrentHp: monster.maxHp,
+        playerState: {
+          attack: playerStats.attack,
+          weaponDamage: playerStats.weaponDamage,
+          armor: playerStats.armor,
+        },
+        monsterState: { attack: monster.attack, armor: monster.armor },
+        completedAt: null,
+      });
+      await combats.save(combat);
+
+      encounter.consumedAt = new Date();
+      await encounters.save(encounter);
+
+      return this.toCombatDto(combat, character.name, monster, []);
+    });
+  }
+
+  async getCombat(characterId: string, combatId: string): Promise<CombatDto> {
+    const combats = this.dataSource.getRepository(Combat);
+    const combat = await combats.findOne({
+      where: { id: combatId, characterId },
+    });
+    if (!combat) {
+      throw combatNotFound();
+    }
+
+    const [character, monster, events] = await Promise.all([
+      this.loadCharacter(combat.characterId),
+      this.loadMonster(combat.monsterDefinitionId),
+      this.loadEvents(combat.id),
+    ]);
+
+    return this.toCombatDto(combat, character.name, monster, events);
+  }
+
+  async performAction(
+    characterId: string,
+    combatId: string,
+    action: CombatAction,
+  ): Promise<CombatDto> {
+    return this.dataSource.transaction(async (manager) => {
+      const combats = manager.getRepository(Combat);
+      const combatEvents = manager.getRepository(CombatEvent);
+
+      const combat = await combats.findOne({
+        where: { id: combatId, characterId },
+        lock: { mode: 'pessimistic_write' },
+      });
+      if (!combat) {
+        throw combatNotFound();
+      }
+      if (combat.status !== CombatStatus.ACTIVE) {
+        throw combatAlreadyFinished();
+      }
+
+      const actionRound = combat.round;
+      const engineState = this.toEngineState(combat);
+      const result = this.combatEngine.resolveAction(engineState, { action });
+
+      combat.round = result.state.round;
+      combat.status = result.state.status;
+      combat.playerCurrentHp = result.state.player.currentHp;
+      combat.monsterCurrentHp = result.state.monster.currentHp;
+      if (combat.status !== CombatStatus.ACTIVE) {
+        combat.completedAt = new Date();
+      }
+      await combats.save(combat);
+
+      const startingSequence = await combatEvents.count({
+        where: { combatId: combat.id },
+      });
+      for (let index = 0; index < result.events.length; index += 1) {
+        const event = result.events[index];
+        const entity = combatEvents.create({
+          combatId: combat.id,
+          round: actionRound,
+          sequence: startingSequence + index + 1,
+          type: event.type,
+          source: event.source,
+          target: event.target,
+          amount: event.amount ?? null,
+        });
+        await combatEvents.save(entity);
+      }
+
+      const [character, monster, events] = await Promise.all([
+        this.loadCharacter(
+          combat.characterId,
+          manager.getRepository(Character),
+        ),
+        this.loadMonster(
+          combat.monsterDefinitionId,
+          manager.getRepository(MonsterDefinition),
+        ),
+        this.loadEvents(combat.id, combatEvents),
+      ]);
+
+      return this.toCombatDto(combat, character.name, monster, events);
+    });
+  }
+
+  private async lockCharacter(
+    characters: Repository<Character>,
+    characterId: string,
+  ): Promise<Character> {
+    const character = await characters.findOne({
+      where: { id: characterId },
+      lock: { mode: 'pessimistic_write' },
+    });
+    if (!character) {
+      throw characterNotFound();
+    }
+    return character;
+  }
+
+  private async loadCharacter(
+    characterId: string,
+    repo?: Repository<Character>,
+  ): Promise<Character> {
+    const characters = repo ?? this.dataSource.getRepository(Character);
+    const character = await characters.findOneBy({ id: characterId });
+    if (!character) {
+      // combats.character_id is a RESTRICT FK; a persisted combat's
+      // character is guaranteed to exist.
+      throw combatStateInvalid();
+    }
+    return character;
+  }
+
+  private async loadMonster(
+    monsterId: string,
+    repo?: Repository<MonsterDefinition>,
+  ): Promise<MonsterDefinition> {
+    const monsters = repo ?? this.dataSource.getRepository(MonsterDefinition);
+    const monster = await monsters.findOneBy({ id: monsterId });
+    if (!monster) {
+      // combats.monster_definition_id is a RESTRICT FK; guaranteed to exist.
+      throw combatStateInvalid();
+    }
+    return monster;
+  }
+
+  private loadEvents(
+    combatId: string,
+    repo?: Repository<CombatEvent>,
+  ): Promise<CombatEvent[]> {
+    const combatEvents = repo ?? this.dataSource.getRepository(CombatEvent);
+    return combatEvents.find({
+      where: { combatId },
+      order: { sequence: 'ASC' },
+    });
+  }
+
+  private toEngineState(combat: Combat): CombatEngineState {
+    return {
+      status: combat.status,
+      round: combat.round,
+      player: {
+        currentHp: combat.playerCurrentHp,
+        maxHp: combat.playerMaxHp,
+        stats: combat.playerState,
+      },
+      monster: {
+        currentHp: combat.monsterCurrentHp,
+        maxHp: combat.monsterMaxHp,
+        stats: combat.monsterState,
+      },
+    };
+  }
+
+  private toCombatDto(
+    combat: Combat,
+    playerName: string,
+    monster: MonsterDefinition,
+    events: CombatEvent[],
+  ): CombatDto {
+    return {
+      id: combat.id,
+      status: combat.status,
+      round: combat.round,
+      player: {
+        name: playerName,
+        maxHp: combat.playerMaxHp,
+        currentHp: combat.playerCurrentHp,
+      },
+      monster: {
+        key: monster.key,
+        name: monster.name,
+        level: monster.level,
+        maxHp: combat.monsterMaxHp,
+        currentHp: combat.monsterCurrentHp,
+        artworkPath: monster.artworkPath,
+      },
+      events: events.map((event) => ({
+        round: event.round,
+        sequence: event.sequence,
+        type: event.type,
+        source: event.source,
+        target: event.target,
+        amount: event.amount ?? undefined,
+      })),
+    };
+  }
+}

apps/api/src/combat/combatant.enum.ts

@@ -0,0 +1,4 @@
+export enum Combatant {
+  PLAYER = 'PLAYER',
+  MONSTER = 'MONSTER',
+}

apps/api/src/combat/dto/combat-action.dto.ts

@@ -0,0 +1,7 @@
+import { IsEnum } from 'class-validator';
+import { CombatAction } from '../combat-action.enum';
+
+export class CombatActionDto {
+  @IsEnum(CombatAction)
+  action!: CombatAction;
+}

apps/api/src/combat/entities/combat-event.entity.ts

@@ -0,0 +1,62 @@
+import {
+  Column,
+  CreateDateColumn,
+  Entity,
+  Index,
+  JoinColumn,
+  ManyToOne,
+  PrimaryGeneratedColumn,
+} from 'typeorm';
+import { Combatant } from '../combatant.enum';
+import { CombatEventType } from '../combat-event-type.enum';
+import { Combat } from './combat.entity';
+
+@Entity({ name: 'combat_events' })
+@Index('IDX_combat_events_combat_sequence', ['combatId', 'sequence'], { unique: true })
+export class CombatEvent {
+  @PrimaryGeneratedColumn('uuid', { name: 'id' })
+  id!: string;
+
+  @Column({ name: 'combat_id', type: 'uuid' })
+  combatId!: string;
+
+  @Column({ name: 'round', type: 'integer' })
+  round!: number;
+
+  @Column({ name: 'sequence', type: 'integer' })
+  sequence!: number;
+
+  @Column({
+    name: 'type',
+    type: 'enum',
+    enum: CombatEventType,
+    enumName: 'combat_event_type_enum',
+  })
+  type!: CombatEventType;
+
+  @Column({
+    name: 'source',
+    type: 'enum',
+    enum: Combatant,
+    enumName: 'combatant_enum',
+  })
+  source!: Combatant;
+
+  @Column({
+    name: 'target',
+    type: 'enum',
+    enum: Combatant,
+    enumName: 'combatant_enum',
+  })
+  target!: Combatant;
+
+  @Column({ name: 'amount', type: 'integer', nullable: true })
+  amount!: number | null;
+
+  @CreateDateColumn({ name: 'created_at', type: 'timestamptz' })
+  createdAt!: Date;
+
+  @ManyToOne(() => Combat, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'combat_id' })
+  combat!: Combat;
+}

apps/api/src/combat/entities/combat.entity.ts

@@ -0,0 +1,89 @@
+import {
+  Column,
+  CreateDateColumn,
+  Entity,
+  Index,
+  JoinColumn,
+  ManyToOne,
+  PrimaryGeneratedColumn,
+  UpdateDateColumn,
+} from 'typeorm';
+import { Character } from '../../characters/entities/character.entity';
+import { HuntEncounter } from '../../hunting/entities/hunt-encounter.entity';
+import { MonsterDefinition } from '../../monsters/entities/monster-definition.entity';
+import { CombatStatus } from '../combat-status.enum';
+
+export interface CombatCombatantState {
+  attack: number;
+  armor: number;
+}
+
+export interface CombatPlayerState extends CombatCombatantState {
+  weaponDamage: number;
+}
+
+@Entity({ name: 'combats' })
+@Index('IDX_combats_hunt_encounter', ['huntEncounterId'], { unique: true })
+export class Combat {
+  @PrimaryGeneratedColumn('uuid', { name: 'id' })
+  id!: string;
+
+  @Column({ name: 'character_id', type: 'uuid' })
+  characterId!: string;
+
+  @Column({ name: 'hunt_encounter_id', type: 'uuid' })
+  huntEncounterId!: string;
+
+  @Column({ name: 'monster_definition_id', type: 'uuid' })
+  monsterDefinitionId!: string;
+
+  @Column({
+    name: 'status',
+    type: 'enum',
+    enum: CombatStatus,
+    enumName: 'combat_status_enum',
+  })
+  status!: CombatStatus;
+
+  @Column({ name: 'round', type: 'integer' })
+  round!: number;
+
+  @Column({ name: 'player_max_hp', type: 'integer' })
+  playerMaxHp!: number;
+
+  @Column({ name: 'player_current_hp', type: 'integer' })
+  playerCurrentHp!: number;
+
+  @Column({ name: 'monster_max_hp', type: 'integer' })
+  monsterMaxHp!: number;
+
+  @Column({ name: 'monster_current_hp', type: 'integer' })
+  monsterCurrentHp!: number;
+
+  @Column({ name: 'player_state', type: 'jsonb' })
+  playerState!: CombatPlayerState;
+
+  @Column({ name: 'monster_state', type: 'jsonb' })
+  monsterState!: CombatCombatantState;
+
+  @CreateDateColumn({ name: 'created_at', type: 'timestamptz' })
+  createdAt!: Date;
+
+  @UpdateDateColumn({ name: 'updated_at', type: 'timestamptz' })
+  updatedAt!: Date;
+
+  @Column({ name: 'completed_at', type: 'timestamptz', nullable: true })
+  completedAt!: Date | null;
+
+  @ManyToOne(() => Character, { onDelete: 'RESTRICT' })
+  @JoinColumn({ name: 'character_id' })
+  character!: Character;
+
+  @ManyToOne(() => HuntEncounter, { onDelete: 'RESTRICT' })
+  @JoinColumn({ name: 'hunt_encounter_id' })
+  huntEncounter!: HuntEncounter;
+
+  @ManyToOne(() => MonsterDefinition, { onDelete: 'RESTRICT' })
+  @JoinColumn({ name: 'monster_definition_id' })
+  monster!: MonsterDefinition;
+}

apps/api/src/combat/hunt-encounter-attack.controller.spec.ts

@@ -0,0 +1,41 @@
+import { INestApplication } from '@nestjs/common';
+import { Test } from '@nestjs/testing';
+import request from 'supertest';
+import { App } from 'supertest/types';
+import { configureApplication } from '../app.config';
+import { DEMO_CHARACTER_ID } from '../demo/demo-character.constants';
+import { CombatService } from './combat.service';
+import { HuntEncounterAttackController } from './hunt-encounter-attack.controller';
+
+describe('HuntEncounterAttackController', () => {
+  let app: INestApplication<App>;
+  const startCombat = jest.fn();
+
+  beforeEach(async () => {
+    startCombat.mockReset();
+    const module = await Test.createTestingModule({
+      controllers: [HuntEncounterAttackController],
+      providers: [{ provide: CombatService, useValue: { startCombat } }],
+    }).compile();
+
+    app = module.createNestApplication<App>();
+    configureApplication(app);
+    await app.init();
+  });
+
+  afterEach(async () => {
+    await app.close();
+  });
+
+  it('delegates to combatService.startCombat with the demo character id and the encounter id', async () => {
+    const combat = { id: 'combat-1', status: 'ACTIVE', round: 1, player: {}, monster: {}, events: [] };
+    startCombat.mockResolvedValue(combat);
+
+    const response = await request(app.getHttpServer())
+      .post('/api/hunt-encounters/encounter-1/attack')
+      .expect(201);
+
+    expect(startCombat).toHaveBeenCalledWith(DEMO_CHARACTER_ID, 'encounter-1');
+    expect(response.body).toEqual(combat);
+  });
+});

apps/api/src/combat/hunt-encounter-attack.controller.ts

@@ -0,0 +1,13 @@
+import { Controller, Param, Post } from '@nestjs/common';
+import { DEMO_CHARACTER_ID } from '../demo/demo-character.constants';
+import { CombatService } from './combat.service';
+
+@Controller('hunt-encounters')
+export class HuntEncounterAttackController {
+  constructor(private readonly combatService: CombatService) {}
+
+  @Post(':encounterId/attack')
+  attack(@Param('encounterId') encounterId: string) {
+    return this.combatService.startCombat(DEMO_CHARACTER_ID, encounterId);
+  }
+}

apps/api/src/database/migrations/1788100000000-CreateCombatSystem.ts

@@ -0,0 +1,89 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+export class CreateCombatSystem1788100000000 implements MigrationInterface {
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      'ALTER TABLE "hunt_encounters" ADD COLUMN "consumed_at" TIMESTAMP WITH TIME ZONE',
+    );
+
+    await queryRunner.query(
+      "CREATE TYPE \"combat_status_enum\" AS ENUM ('ACTIVE', 'WON', 'LOST')",
+    );
+    await queryRunner.query(
+      "CREATE TYPE \"combat_event_type_enum\" AS ENUM ('DAMAGE', 'COMBAT_WON', 'COMBAT_LOST')",
+    );
+    await queryRunner.query(
+      "CREATE TYPE \"combatant_enum\" AS ENUM ('PLAYER', 'MONSTER')",
+    );
+
+    await queryRunner.query(`CREATE TABLE "combats" (
+      "id" uuid NOT NULL DEFAULT gen_random_uuid(),
+      "character_id" uuid NOT NULL,
+      "hunt_encounter_id" uuid NOT NULL,
+      "monster_definition_id" uuid NOT NULL,
+      "status" "combat_status_enum" NOT NULL,
+      "round" integer NOT NULL,
+      "player_max_hp" integer NOT NULL,
+      "player_current_hp" integer NOT NULL,
+      "monster_max_hp" integer NOT NULL,
+      "monster_current_hp" integer NOT NULL,
+      "player_state" jsonb NOT NULL,
+      "monster_state" jsonb NOT NULL,
+      "created_at" TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT now(),
+      "updated_at" TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT now(),
+      "completed_at" TIMESTAMP WITH TIME ZONE,
+      CONSTRAINT "PK_combats" PRIMARY KEY ("id"),
+      CONSTRAINT "FK_combats_character" FOREIGN KEY ("character_id") REFERENCES "characters"("id") ON DELETE RESTRICT ON UPDATE NO ACTION,
+      CONSTRAINT "FK_combats_hunt_encounter" FOREIGN KEY ("hunt_encounter_id") REFERENCES "hunt_encounters"("id") ON DELETE RESTRICT ON UPDATE NO ACTION,
+      CONSTRAINT "FK_combats_monster_definition" FOREIGN KEY ("monster_definition_id") REFERENCES "monster_definitions"("id") ON DELETE RESTRICT ON UPDATE NO ACTION
+    )`);
+    await queryRunner.query(
+      'CREATE INDEX "IDX_combats_character" ON "combats" ("character_id")',
+    );
+    await queryRunner.query(
+      'CREATE UNIQUE INDEX "IDX_combats_hunt_encounter" ON "combats" ("hunt_encounter_id")',
+    );
+    await queryRunner.query(
+      'CREATE INDEX "IDX_combats_monster_definition" ON "combats" ("monster_definition_id")',
+    );
+    await queryRunner.query(`CREATE UNIQUE INDEX "IDX_active_combat_per_character"
+      ON "combats" ("character_id")
+      WHERE "status" = 'ACTIVE'`);
+
+    await queryRunner.query(`CREATE TABLE "combat_events" (
+      "id" uuid NOT NULL DEFAULT gen_random_uuid(),
+      "combat_id" uuid NOT NULL,
+      "round" integer NOT NULL,
+      "sequence" integer NOT NULL,
+      "type" "combat_event_type_enum" NOT NULL,
+      "source" "combatant_enum" NOT NULL,
+      "target" "combatant_enum" NOT NULL,
+      "amount" integer,
+      "created_at" TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT now(),
+      CONSTRAINT "PK_combat_events" PRIMARY KEY ("id"),
+      CONSTRAINT "FK_combat_events_combat" FOREIGN KEY ("combat_id") REFERENCES "combats"("id") ON DELETE CASCADE ON UPDATE NO ACTION
+    )`);
+    await queryRunner.query(
+      'CREATE INDEX "IDX_combat_events_combat" ON "combat_events" ("combat_id")',
+    );
+    await queryRunner.query(`CREATE UNIQUE INDEX "IDX_combat_events_combat_sequence"
+      ON "combat_events" ("combat_id", "sequence")`);
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query('DROP INDEX "IDX_combat_events_combat_sequence"');
+    await queryRunner.query('DROP INDEX "IDX_combat_events_combat"');
+    await queryRunner.query('DROP TABLE "combat_events"');
+    await queryRunner.query('DROP INDEX "IDX_active_combat_per_character"');
+    await queryRunner.query('DROP INDEX "IDX_combats_monster_definition"');
+    await queryRunner.query('DROP INDEX "IDX_combats_hunt_encounter"');
+    await queryRunner.query('DROP INDEX "IDX_combats_character"');
+    await queryRunner.query('DROP TABLE "combats"');
+    await queryRunner.query('DROP TYPE "combatant_enum"');
+    await queryRunner.query('DROP TYPE "combat_event_type_enum"');
+    await queryRunner.query('DROP TYPE "combat_status_enum"');
+    await queryRunner.query(
+      'ALTER TABLE "hunt_encounters" DROP COLUMN "consumed_at"',
+    );
+  }
+}

apps/api/src/database/migrations/combat-system.migration.spec.ts

@@ -0,0 +1,65 @@
+import 'reflect-metadata';
+import { getMetadataArgsStorage } from 'typeorm';
+import { Combat } from '../../combat/entities/combat.entity';
+import { CombatEvent } from '../../combat/entities/combat-event.entity';
+import { HuntEncounter } from '../../hunting/entities/hunt-encounter.entity';
+
+describe('combat system schema', () => {
+  it('maps Combat and CombatEvent relations with the documented onDelete behavior', () => {
+    const metadata = getMetadataArgsStorage();
+
+    const relations = metadata.relations.filter(
+      (relation) => relation.target === Combat || relation.target === CombatEvent,
+    );
+
+    expect(
+      relations.map((relation) => ({
+        onDelete: relation.options.onDelete,
+        propertyName: relation.propertyName,
+        target: relation.target,
+      })),
+    ).toEqual(
+      expect.arrayContaining([
+        expect.objectContaining({ onDelete: 'RESTRICT', propertyName: 'character', target: Combat }),
+        expect.objectContaining({ onDelete: 'RESTRICT', propertyName: 'huntEncounter', target: Combat }),
+        expect.objectContaining({ onDelete: 'RESTRICT', propertyName: 'monster', target: Combat }),
+        expect.objectContaining({ onDelete: 'CASCADE', propertyName: 'combat', target: CombatEvent }),
+      ]),
+    );
+  });
+
+  it('enforces one combat per hunt encounter via a unique index', () => {
+    const metadata = getMetadataArgsStorage();
+    const index = metadata.indices.find(
+      (candidate) => candidate.target === Combat && candidate.columns?.includes('huntEncounterId'),
+    );
+
+    expect(index).toBeDefined();
+    const indexMetadata = index as typeof index & { options?: { unique?: boolean }; unique?: boolean };
+    expect(indexMetadata?.options?.unique ?? indexMetadata?.unique).toBe(true);
+  });
+
+  it('enforces ordered, unique event sequencing per combat', () => {
+    const metadata = getMetadataArgsStorage();
+    const index = metadata.indices.find(
+      (candidate) =>
+        candidate.target === CombatEvent &&
+        candidate.columns?.includes('combatId') &&
+        candidate.columns?.includes('sequence'),
+    );
+
+    expect(index).toBeDefined();
+    const indexMetadata = index as typeof index & { options?: { unique?: boolean }; unique?: boolean };
+    expect(indexMetadata?.options?.unique ?? indexMetadata?.unique).toBe(true);
+  });
+
+  it('adds a nullable consumedAt column to hunt_encounters to prevent reuse', () => {
+    const metadata = getMetadataArgsStorage();
+    const column = metadata.columns.find(
+      (candidate) => candidate.target === HuntEncounter && candidate.propertyName === 'consumedAt',
+    );
+
+    expect(column).toBeDefined();
+    expect(column?.options.nullable).toBe(true);
+  });
+});

apps/api/src/hunting/entities/hunt-encounter.entity.ts

@@ -23,6 +23,11 @@ export class HuntEncounter {
   @Column({ name: 'position', type: 'integer' })
   position!: number;
 
+  // Set when a Combat is successfully created from this encounter. Prevents
+  // one HuntEncounter from spawning more than one Combat (spec §7).
+  @Column({ name: 'consumed_at', type: 'timestamptz', nullable: true })
+  consumedAt!: Date | null;
+
   @CreateDateColumn({ name: 'created_at', type: 'timestamptz' })
   createdAt!: Date;
 

apps/web/src/app/app.routes.ts

@@ -22,10 +22,10 @@ export const routes: Routes = [
           ),
       },
       {
-        path: 'combat/new',
+        path: 'combat/:combatId',
         loadComponent: () =>
-          import('./features/combat/combat-placeholder-page.component').then(
-            (module) => module.CombatPlaceholderPageComponent,
+          import('./features/combat/combat-page/combat-page.component').then(
+            (module) => module.CombatPageComponent,
           ),
       },
     ],

apps/web/src/app/core/api/game-api.models.ts

@@ -68,3 +68,41 @@ export interface HuntResult {
   location: LocationSummary;
   encounters: HuntEncounter[];
 }
+
+export type CombatStatus = 'ACTIVE' | 'WON' | 'LOST';
+export type CombatEventType = 'DAMAGE' | 'COMBAT_WON' | 'COMBAT_LOST';
+export type CombatSide = 'PLAYER' | 'MONSTER';
+export type CombatAction = 'ATTACK';
+
+export interface CombatEvent {
+  round: number;
+  sequence: number;
+  type: CombatEventType;
+  source: CombatSide;
+  target: CombatSide;
+  amount?: number;
+}
+
+export interface CombatPlayer {
+  name: string;
+  maxHp: number;
+  currentHp: number;
+}
+
+export interface CombatMonster {
+  key: string;
+  name: string;
+  level: number;
+  maxHp: number;
+  currentHp: number;
+  artworkPath: string;
+}
+
+export interface Combat {
+  id: string;
+  status: CombatStatus;
+  round: number;
+  player: CombatPlayer;
+  monster: CombatMonster;
+  events: CombatEvent[];
+}

apps/web/src/app/core/api/game-api.service.spec.ts

@@ -47,4 +47,30 @@ describe('GameApiService', () => {
     expect(request.request.body).toEqual({ targetLocationId: 'target-uuid' });
     request.flush({ status: 'IDLE' });
   });
+
+  it('posts to the encounter-scoped attack endpoint with an empty body to start a combat', () => {
+    service.startCombat('encounter-uuid').subscribe();
+
+    const request = http.expectOne('/api/hunt-encounters/encounter-uuid/attack');
+    expect(request.request.method).toBe('POST');
+    expect(request.request.body).toEqual({});
+    request.flush({});
+  });
+
+  it('gets a combat by id', () => {
+    service.getCombat('combat-uuid').subscribe();
+
+    const request = http.expectOne('/api/combats/combat-uuid');
+    expect(request.request.method).toBe('GET');
+    request.flush({});
+  });
+
+  it('posts only the action enum when performing a combat action', () => {
+    service.performCombatAction('combat-uuid', 'ATTACK').subscribe();
+
+    const request = http.expectOne('/api/combats/combat-uuid/actions');
+    expect(request.request.method).toBe('POST');
+    expect(request.request.body).toEqual({ action: 'ATTACK' });
+    request.flush({});
+  });
 });

apps/web/src/app/core/api/game-api.service.ts

@@ -1,7 +1,14 @@
 import { HttpClient } from '@angular/common/http';
 import { Injectable } from '@angular/core';
 import { Observable } from 'rxjs';
-import { CharacterResponse, CurrentLocationResponse, CurrentTravel, HuntResult } from './game-api.models';
+import {
+  CharacterResponse,
+  Combat,
+  CombatAction,
+  CurrentLocationResponse,
+  CurrentTravel,
+  HuntResult,
+} from './game-api.models';
 
 @Injectable({ providedIn: 'root' })
 export class GameApiService {
@@ -26,4 +33,16 @@ export class GameApiService {
   startHunt(): Observable<HuntResult> {
     return this.http.post<HuntResult>('/api/hunts', {});
   }
+
+  startCombat(encounterId: string): Observable<Combat> {
+    return this.http.post<Combat>(`/api/hunt-encounters/${encounterId}/attack`, {});
+  }
+
+  getCombat(combatId: string): Observable<Combat> {
+    return this.http.get<Combat>(`/api/combats/${combatId}`);
+  }
+
+  performCombatAction(combatId: string, action: CombatAction): Observable<Combat> {
+    return this.http.post<Combat>(`/api/combats/${combatId}/actions`, { action });
+  }
 }

apps/web/src/app/features/combat/combat-page/combat-page.component.html

@@ -0,0 +1,119 @@
+<section class="combat" aria-label="Kampf">
+  @if (combatStore.combat(); as combat) {
+    <div class="combat__stage">
+      <header class="combat__status">
+        <div class="fighter fighter--player">
+          <img class="fighter__icon" [src]="playerIcon" alt="" />
+          <div class="fighter__meter">
+            <p class="fighter__name">{{ combat.player.name }}</p>
+            <div
+              class="bar bar--player"
+              role="progressbar"
+              [attr.aria-label]="'Lebenspunkte ' + combat.player.name"
+              [attr.aria-valuenow]="combat.player.currentHp"
+              [attr.aria-valuemin]="0"
+              [attr.aria-valuemax]="combat.player.maxHp"
+            >
+              <span class="bar__fill" [style.inline-size.%]="playerHpPercent()"></span>
+              <span class="bar__text">{{ combat.player.currentHp }} / {{ combat.player.maxHp }}</span>
+            </div>
+          </div>
+        </div>
+
+        <p class="combat__round" data-combat-round>Runde {{ combat.round }}</p>
+
+        <div class="fighter fighter--monster">
+          <div class="fighter__meter">
+            <p class="fighter__name">
+              {{ combat.monster.name }}
+              <span class="fighter__level">Stufe {{ combat.monster.level }}</span>
+            </p>
+            <div
+              class="bar bar--monster"
+              role="progressbar"
+              [attr.aria-label]="'Lebenspunkte ' + combat.monster.name"
+              [attr.aria-valuenow]="combat.monster.currentHp"
+              [attr.aria-valuemin]="0"
+              [attr.aria-valuemax]="combat.monster.maxHp"
+            >
+              <span class="bar__fill" [style.inline-size.%]="monsterHpPercent()"></span>
+              <span class="bar__text">{{ combat.monster.currentHp }} / {{ combat.monster.maxHp }}</span>
+            </div>
+          </div>
+          <img
+            class="fighter__icon"
+            [src]="monsterIcon(combat.monster.key, combat.monster.artworkPath)"
+            alt=""
+          />
+        </div>
+      </header>
+
+      <div class="combat__field">
+        <img class="sprite sprite--player" [src]="playerSprite" [alt]="combat.player.name" />
+        <img
+          class="sprite sprite--monster"
+          [src]="monsterSprite(combat.monster.key, combat.monster.artworkPath)"
+          [alt]="combat.monster.name"
+        />
+      </div>
+
+      <footer class="combat__actions">
+        @if (combat.status === 'ACTIVE') {
+          <button
+            type="button"
+            class="action"
+            data-combat-attack
+            [disabled]="combatStore.actionPending()"
+            (click)="attack()"
+          >
+            <img class="action__icon" src="/images/hud/runtime/AttackIcon-96.png" alt="" />
+            <span class="action__label">Angriff</span>
+            <span class="action__key">1</span>
+          </button>
+        }
+      </footer>
+
+      @if (combat.status === 'WON') {
+        <div class="outcome outcome--won" data-combat-result="WON">
+          <h2 class="outcome__title">Sieg</h2>
+          <p>{{ combat.monster.name }} wurde besiegt.</p>
+          <p class="outcome__hint">Belohnungen werden im nächsten Schritt verarbeitet.</p>
+          <button type="button" class="outcome__button" data-combat-to-hunt (click)="goToHunt()">
+            Zur Jagd
+          </button>
+        </div>
+      } @else if (combat.status === 'LOST') {
+        <div class="outcome outcome--lost" data-combat-result="LOST">
+          <h2 class="outcome__title">Niederlage</h2>
+          <p>{{ combat.player.name }} wurde im Kampf besiegt.</p>
+          <button type="button" class="outcome__button" data-combat-to-hunt (click)="goToHunt()">
+            Zur Jagd
+          </button>
+        </div>
+      }
+    </div>
+
+    <aside class="combat__log" aria-label="Kampfprotokoll">
+      <h2 class="combat__log-title">Kampflog</h2>
+      <div class="combat__log-body">
+        @for (round of logRounds(); track round.round) {
+          <p class="combat__log-round">Runde {{ round.round }}</p>
+          @for (event of round.events; track event.sequence) {
+            <p class="combat__log-entry" [class.combat__log-entry--player]="event.source === 'PLAYER'">
+              {{ formatEvent(event) }}
+            </p>
+          }
+        }
+      </div>
+    </aside>
+  } @else if (combatStore.loading()) {
+    <p class="combat__notice" role="status">Kampf wird geladen…</p>
+  }
+
+  @if (combatStore.error(); as error) {
+    <section class="combat__notice combat__notice--error" role="alert">
+      <p>{{ error }}</p>
+      <button type="button" data-combat-retry (click)="retry()">Erneut versuchen</button>
+    </section>
+  }
+</section>

apps/web/src/app/features/combat/combat-page/combat-page.component.scss

@@ -0,0 +1,479 @@
+:host {
+  display: block;
+  block-size: 100%;
+}
+
+.combat {
+  display: grid;
+  grid-template-columns: minmax(0, 1fr) clamp(13rem, 17vw, 17rem);
+  gap: var(--ar-space-4);
+  block-size: 100%;
+}
+
+/* ---------- stage ---------- */
+
+.combat__stage {
+  position: relative;
+  display: grid;
+  grid-template-rows: auto minmax(0, 1fr) auto;
+  gap: var(--ar-space-4);
+  min-block-size: 26rem;
+  padding: var(--ar-space-4);
+  overflow: hidden;
+  border: 1px solid var(--ar-border);
+  background-color: var(--ar-bg);
+  background-image: url('/images/backgrounds/Aschestrasse.png');
+  background-position: center;
+  background-repeat: no-repeat;
+  background-size: cover;
+  box-shadow: var(--ar-shadow-raised);
+}
+
+@supports (
+  background-image: image-set(
+      url('/images/backgrounds/runtime/Aschestrasse-960.jpg') type('image/jpeg') 1x
+    )
+) {
+  .combat__stage {
+    background-image: image-set(
+      url('/images/backgrounds/runtime/Aschestrasse-960.jpg') type('image/jpeg') 1x
+    );
+  }
+}
+
+.combat__stage::before {
+  position: absolute;
+  z-index: 0;
+  inset: 0;
+  content: '';
+  background:
+    linear-gradient(180deg, rgb(4 6 8 / 0.72) 0%, rgb(4 6 8 / 0.1) 26%, rgb(4 6 8 / 0.66) 100%);
+  pointer-events: none;
+}
+
+/* ---------- combatant status ---------- */
+
+.combat__status {
+  position: relative;
+  z-index: 2;
+  display: grid;
+  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
+  align-items: start;
+  gap: var(--ar-space-4);
+}
+
+.fighter {
+  display: flex;
+  align-items: center;
+  gap: var(--ar-space-3);
+  min-inline-size: 0;
+}
+
+.fighter--monster {
+  justify-content: flex-end;
+}
+
+.fighter__icon {
+  flex: 0 0 auto;
+  inline-size: clamp(2.75rem, 5vw, 3.75rem);
+  block-size: clamp(2.75rem, 5vw, 3.75rem);
+  object-fit: cover;
+  border-radius: 50%;
+  box-shadow:
+    0 0 0 1px var(--ar-border-highlight),
+    0 0.3rem 0.9rem rgb(0 0 0 / 0.8);
+}
+
+.fighter__meter {
+  display: grid;
+  gap: 0.3rem;
+  min-inline-size: 0;
+  flex: 1 1 auto;
+  max-inline-size: 22rem;
+}
+
+.fighter--monster .fighter__meter {
+  justify-items: end;
+  text-align: end;
+}
+
+.fighter__name {
+  margin: 0;
+  overflow: hidden;
+  color: var(--ar-text);
+  font-family: Georgia, 'Times New Roman', serif;
+  font-size: clamp(0.95rem, 1.5vw, 1.15rem);
+  letter-spacing: 0.02em;
+  text-overflow: ellipsis;
+  text-shadow: 0 0.1rem 0.5rem rgb(0 0 0 / 0.95);
+  white-space: nowrap;
+}
+
+.fighter__level {
+  color: var(--ar-gold);
+  font-family: system-ui, sans-serif;
+  font-size: var(--ar-font-sm);
+  letter-spacing: 0.08em;
+  text-transform: uppercase;
+}
+
+/* ---------- hp bars ---------- */
+
+.bar {
+  position: relative;
+  display: block;
+  inline-size: 100%;
+  block-size: 1.25rem;
+  overflow: hidden;
+  border: 1px solid var(--ar-border);
+  background: linear-gradient(180deg, rgb(0 0 0 / 0.85), rgb(0 0 0 / 0.6));
+  box-shadow: inset 0 0 0.6rem rgb(0 0 0 / 0.9);
+}
+
+.bar__fill {
+  position: absolute;
+  z-index: 0;
+  inset-block: 0;
+  inset-inline-start: 0;
+  display: block;
+  background: linear-gradient(180deg, #d0564a, #8e2b23);
+}
+
+.bar--monster .bar__fill {
+  inset-inline-start: auto;
+  inset-inline-end: 0;
+}
+
+.bar__text {
+  position: relative;
+  z-index: 1;
+  display: grid;
+  block-size: 100%;
+  place-items: center;
+  color: var(--ar-text);
+  font-size: var(--ar-font-sm);
+  font-variant-numeric: tabular-nums;
+  letter-spacing: 0.04em;
+  text-shadow: 0 0.05rem 0.25rem rgb(0 0 0 / 1);
+}
+
+/* ---------- round marker ---------- */
+
+.combat__round {
+  margin: 0;
+  align-self: center;
+  padding: var(--ar-space-1) var(--ar-space-5);
+  border-block: 1px solid var(--ar-border-highlight);
+  color: var(--ar-gold);
+  background: linear-gradient(90deg, transparent, rgb(9 11 13 / 0.9) 18%, rgb(9 11 13 / 0.9) 82%, transparent);
+  font-family: Georgia, 'Times New Roman', serif;
+  font-size: clamp(0.95rem, 1.4vw, 1.1rem);
+  letter-spacing: 0.14em;
+  text-transform: uppercase;
+  white-space: nowrap;
+}
+
+/* ---------- battlefield ---------- */
+
+.combat__field {
+  position: relative;
+  z-index: 1;
+  display: grid;
+  grid-template-columns: 1fr 1fr;
+  align-items: end;
+  min-block-size: 0;
+}
+
+.sprite {
+  display: block;
+  max-block-size: 100%;
+  inline-size: auto;
+  object-fit: contain;
+  filter: drop-shadow(0 1rem 1.5rem rgb(0 0 0 / 0.75));
+}
+
+.sprite--player {
+  justify-self: start;
+  block-size: clamp(11rem, 30vh, 19rem);
+  transform: scaleX(-1);
+}
+
+.sprite--monster {
+  justify-self: end;
+  block-size: clamp(9rem, 24vh, 15rem);
+}
+
+/* ---------- action bar ---------- */
+
+.combat__actions {
+  position: relative;
+  z-index: 2;
+  display: flex;
+  gap: var(--ar-space-3);
+  min-block-size: clamp(6.5rem, 11vw, 8.5rem);
+}
+
+.action {
+  position: relative;
+  inline-size: clamp(6.5rem, 11vw, 8.5rem);
+  aspect-ratio: 1;
+  padding: 0;
+  border: 0;
+  background: transparent url('/images/hud/runtime/fight-action-frame-360.png') center / 100% 100%
+    no-repeat;
+  cursor: pointer;
+}
+
+.action__icon {
+  position: absolute;
+  inset-block-start: 32%;
+  inset-inline-start: 50%;
+  inline-size: 34%;
+  translate: -50% -50%;
+  border-radius: 50%;
+  opacity: 0.92;
+}
+
+.action__label {
+  position: absolute;
+  inset-block-start: 62%;
+  inset-inline-start: 50%;
+  translate: -50% -50%;
+  color: var(--ar-text);
+  font-family: Georgia, 'Times New Roman', serif;
+  font-size: clamp(0.85rem, 1.2vw, 1rem);
+  letter-spacing: 0.03em;
+  white-space: nowrap;
+}
+
+.action__key {
+  position: absolute;
+  inset-block-start: 90%;
+  inset-inline-start: 50%;
+  translate: -50% -50%;
+  color: var(--ar-text-muted);
+  font-size: var(--ar-font-sm);
+  font-variant-numeric: tabular-nums;
+}
+
+.action:hover:not(:disabled) .action__label,
+.action:focus-visible .action__label {
+  color: var(--ar-gold);
+}
+
+.action:focus-visible {
+  outline: 2px solid var(--ar-gold);
+  outline-offset: 3px;
+}
+
+.action:disabled {
+  cursor: progress;
+  opacity: 0.55;
+}
+
+/* ---------- outcome overlay ---------- */
+
+.outcome {
+  position: absolute;
+  z-index: 3;
+  inset-block-start: 50%;
+  inset-inline-start: 50%;
+  display: grid;
+  gap: var(--ar-space-2);
+  justify-items: center;
+  inline-size: min(26rem, 80%);
+  padding: var(--ar-space-5);
+  translate: -50% -50%;
+  border: 1px solid var(--ar-border-highlight);
+  background: rgb(9 11 13 / 0.94);
+  box-shadow: var(--ar-shadow-raised);
+  text-align: center;
+}
+
+.outcome p {
+  margin: 0;
+  color: var(--ar-text-muted);
+}
+
+.outcome__title {
+  margin: 0;
+  font-family: Georgia, 'Times New Roman', serif;
+  font-size: clamp(1.5rem, 3vw, 2rem);
+  font-weight: 400;
+  letter-spacing: 0.12em;
+  text-transform: uppercase;
+}
+
+.outcome--won .outcome__title {
+  color: var(--ar-gold);
+}
+
+.outcome--lost .outcome__title {
+  color: var(--ar-danger);
+}
+
+.outcome__hint {
+  font-size: var(--ar-font-sm);
+  font-style: italic;
+}
+
+.outcome__button {
+  margin-block-start: var(--ar-space-2);
+  padding: var(--ar-space-2) var(--ar-space-5);
+  border: 1px solid var(--ar-border-highlight);
+  border-radius: var(--ar-radius-sm);
+  color: var(--ar-text);
+  background: linear-gradient(180deg, #23282c, #14181b);
+  cursor: pointer;
+  font-family: Georgia, 'Times New Roman', serif;
+  letter-spacing: 0.04em;
+}
+
+.outcome__button:hover {
+  border-color: var(--ar-gold);
+  color: var(--ar-gold);
+}
+
+/* ---------- combat log ---------- */
+
+.combat__log {
+  display: grid;
+  grid-template-rows: auto minmax(0, 1fr);
+  min-block-size: 0;
+  border: 1px solid var(--ar-border);
+  background: var(--ar-panel-muted);
+  box-shadow: var(--ar-shadow-raised);
+}
+
+.combat__log-title {
+  margin: 0;
+  padding: var(--ar-space-3) var(--ar-space-4);
+  border-block-end: 1px solid var(--ar-border);
+  color: var(--ar-gold);
+  font-family: Georgia, 'Times New Roman', serif;
+  font-size: 1.05rem;
+  font-weight: 400;
+  letter-spacing: 0.1em;
+  text-transform: uppercase;
+}
+
+.combat__log-body {
+  padding: var(--ar-space-3) var(--ar-space-4) var(--ar-space-4);
+  overflow-y: auto;
+}
+
+.combat__log-round {
+  margin: var(--ar-space-4) 0 var(--ar-space-2);
+  color: var(--ar-gold);
+  font-size: var(--ar-font-sm);
+  letter-spacing: 0.1em;
+  text-transform: uppercase;
+}
+
+.combat__log-round:first-child {
+  margin-block-start: 0;
+}
+
+.combat__log-entry {
+  margin: 0 0 var(--ar-space-1);
+  padding-inline-start: var(--ar-space-3);
+  border-inline-start: 2px solid var(--ar-danger);
+  color: var(--ar-text-muted);
+  font-size: var(--ar-font-sm);
+  line-height: 1.45;
+}
+
+.combat__log-entry--player {
+  border-inline-start-color: var(--ar-border-highlight);
+}
+
+/* ---------- notices ---------- */
+
+.combat__notice {
+  grid-column: 1 / -1;
+  padding: var(--ar-space-4);
+  border: 1px solid var(--ar-border);
+  background: var(--ar-panel);
+  box-shadow: var(--ar-shadow-raised);
+}
+
+.combat__notice--error {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: var(--ar-space-4);
+  border-color: var(--ar-danger);
+}
+
+.combat__notice--error button {
+  flex: 0 0 auto;
+  padding: var(--ar-space-2) var(--ar-space-3);
+  border: 1px solid var(--ar-border-highlight);
+  border-radius: var(--ar-radius-sm);
+  color: var(--ar-text);
+  background: #1a2023;
+  cursor: pointer;
+}
+
+@media (prefers-reduced-motion: no-preference) {
+  .bar__fill {
+    transition: inline-size var(--ar-motion-base);
+  }
+
+  .action__label {
+    transition: color var(--ar-motion-fast);
+  }
+}
+
+@media (width < 60rem) {
+  :host,
+  .combat {
+    block-size: auto;
+  }
+
+  .combat {
+    grid-template-columns: minmax(0, 1fr);
+  }
+
+  .combat__stage {
+    min-block-size: clamp(24rem, 55vh, 34rem);
+  }
+
+  .combat__log {
+    max-block-size: 18rem;
+  }
+}
+
+@media (width < 40rem) {
+  .combat__status {
+    grid-template-columns: minmax(0, 1fr);
+    gap: var(--ar-space-2);
+  }
+
+  .combat__round {
+    order: -1;
+    justify-self: center;
+  }
+
+  .fighter--monster {
+    justify-content: flex-start;
+  }
+
+  .fighter--monster .fighter__meter {
+    justify-items: start;
+    text-align: start;
+  }
+
+  .bar--monster .bar__fill {
+    inset-inline-start: 0;
+    inset-inline-end: auto;
+  }
+
+  .sprite--player {
+    block-size: clamp(8rem, 22vh, 12rem);
+  }
+
+  .sprite--monster {
+    block-size: clamp(7rem, 18vh, 10rem);
+  }
+}

apps/web/src/app/features/combat/combat-page/combat-page.component.spec.ts

@@ -0,0 +1,153 @@
+import { signal } from '@angular/core';
+import { TestBed } from '@angular/core/testing';
+import { ActivatedRoute, convertToParamMap, Router, provideRouter } from '@angular/router';
+import { vi } from 'vitest';
+import type { Combat } from '../../../core/api/game-api.models';
+import { CombatStore } from '../combat.store';
+import { CombatPageComponent } from './combat-page.component';
+
+const activeCombat: Combat = {
+  id: 'combat-1',
+  status: 'ACTIVE',
+  round: 2,
+  player: { name: 'Aric Duskwalker', maxHp: 100, currentHp: 95 },
+  monster: {
+    key: 'ash-rat',
+    name: 'Aschenratte',
+    level: 1,
+    maxHp: 45,
+    currentHp: 31,
+    artworkPath: '/images/monsters/ash-rat.png',
+  },
+  events: [
+    { round: 1, sequence: 1, type: 'DAMAGE', source: 'PLAYER', target: 'MONSTER', amount: 14 },
+    { round: 1, sequence: 2, type: 'DAMAGE', source: 'MONSTER', target: 'PLAYER', amount: 5 },
+  ],
+};
+
+describe('CombatPageComponent', () => {
+  let combatStore: {
+    combat: ReturnType<typeof signal<Combat | null>>;
+    loading: ReturnType<typeof signal<boolean>>;
+    actionPending: ReturnType<typeof signal<boolean>>;
+    error: ReturnType<typeof signal<string | null>>;
+    loadCombat: ReturnType<typeof vi.fn>;
+    attack: ReturnType<typeof vi.fn>;
+  };
+  let router: Router;
+
+  async function setup(combat: Combat | null) {
+    combatStore = {
+      combat: signal(combat),
+      loading: signal(false),
+      actionPending: signal(false),
+      error: signal<string | null>(null),
+      loadCombat: vi.fn(() => Promise.resolve()),
+      attack: vi.fn(() => Promise.resolve()),
+    };
+
+    await TestBed.configureTestingModule({
+      imports: [CombatPageComponent],
+      providers: [
+        provideRouter([]),
+        { provide: CombatStore, useValue: combatStore },
+        {
+          provide: ActivatedRoute,
+          useValue: { snapshot: { paramMap: convertToParamMap({ combatId: 'combat-1' }) } },
+        },
+      ],
+    }).compileComponents();
+
+    router = TestBed.inject(Router);
+    vi.spyOn(router, 'navigate').mockResolvedValue(true);
+
+    const fixture = TestBed.createComponent(CombatPageComponent);
+    fixture.detectChanges();
+    return fixture;
+  }
+
+  it('loads the combat from the route param on init', async () => {
+    await setup(activeCombat);
+
+    expect(combatStore.loadCombat).toHaveBeenCalledWith('combat-1');
+  });
+
+  it('shows the player, monster, HP bars, round, and the Angriff action', async () => {
+    const fixture = await setup(activeCombat);
+    const element = fixture.nativeElement as HTMLElement;
+
+    expect(element.textContent).toContain('Aric Duskwalker');
+    expect(element.textContent).toContain('95 / 100');
+    expect(element.textContent).toContain('Aschenratte');
+    expect(element.textContent).toContain('31 / 45');
+    expect(element.querySelector('[data-combat-round]')?.textContent).toContain('Runde 2');
+    expect(element.querySelector('[data-combat-attack]')).toBeTruthy();
+  });
+
+  it('renders the structured events as readable German combat-log entries', async () => {
+    const fixture = await setup(activeCombat);
+    const element = fixture.nativeElement as HTMLElement;
+
+    expect(element.textContent).toContain('Aric Duskwalker trifft Aschenratte für 14 Schaden.');
+    expect(element.textContent).toContain('Aschenratte trifft Aric Duskwalker für 5 Schaden.');
+  });
+
+  it('calls combatStore.attack() when Angriff is clicked', async () => {
+    const fixture = await setup(activeCombat);
+    const element = fixture.nativeElement as HTMLElement;
+
+    element.querySelector<HTMLButtonElement>('[data-combat-attack]')?.click();
+
+    expect(combatStore.attack).toHaveBeenCalledOnce();
+  });
+
+  it('disables Angriff while an action is pending', async () => {
+    const fixture = await setup(activeCombat);
+    combatStore.actionPending.set(true);
+    fixture.detectChanges();
+
+    const element = fixture.nativeElement as HTMLElement;
+    expect(element.querySelector<HTMLButtonElement>('[data-combat-attack]')?.disabled).toBe(true);
+  });
+
+  it('shows the victory state and hides Angriff when the combat is WON', async () => {
+    const fixture = await setup({ ...activeCombat, status: 'WON' });
+    const element = fixture.nativeElement as HTMLElement;
+
+    expect(element.querySelector('[data-combat-result="WON"]')).toBeTruthy();
+    expect(element.textContent).toContain('Sieg');
+    expect(element.querySelector('[data-combat-attack]')).toBeNull();
+  });
+
+  it('shows the defeat state and hides Angriff when the combat is LOST', async () => {
+    const fixture = await setup({ ...activeCombat, status: 'LOST' });
+    const element = fixture.nativeElement as HTMLElement;
+
+    expect(element.querySelector('[data-combat-result="LOST"]')).toBeTruthy();
+    expect(element.textContent).toContain('Niederlage');
+    expect(element.querySelector('[data-combat-attack]')).toBeNull();
+  });
+
+  it('navigates to /hunt from the victory screen', async () => {
+    const fixture = await setup({ ...activeCombat, status: 'WON' });
+    const element = fixture.nativeElement as HTMLElement;
+
+    element.querySelector<HTMLButtonElement>('[data-combat-to-hunt]')?.click();
+
+    expect(router.navigate).toHaveBeenCalledWith(['/hunt']);
+  });
+
+  it('shows an error and retries loading the combat', async () => {
+    const fixture = await setup(null);
+    combatStore.error.set('Dieser Kampf wurde nicht gefunden.');
+    fixture.detectChanges();
+
+    const element = fixture.nativeElement as HTMLElement;
+    expect(element.querySelector('[role="alert"]')?.textContent).toContain(
+      'Dieser Kampf wurde nicht gefunden.',
+    );
+    element.querySelector<HTMLButtonElement>('[data-combat-retry]')?.click();
+
+    expect(combatStore.loadCombat).toHaveBeenCalledTimes(2);
+  });
+});

apps/web/src/app/features/combat/combat-page/combat-page.component.ts

@@ -0,0 +1,106 @@
+import { Component, OnInit, inject } from '@angular/core';
+import { ActivatedRoute, Router } from '@angular/router';
+import type { CombatEvent } from '../../../core/api/game-api.models';
+import {
+  combatMonsterIconPath,
+  combatMonsterSpritePath,
+  runtimeMonsterArtworkPath,
+} from '../../../shared/monster-artwork';
+import { CombatStore } from '../combat.store';
+
+interface CombatLogRound {
+  round: number;
+  events: CombatEvent[];
+}
+
+const PLAYER_SPRITE = '/images/combat/sprites/warrior-attack-512.png';
+const PLAYER_ICON = '/images/hud/runtime/CharacterIcon-128.png';
+
+@Component({
+  selector: 'app-combat-page',
+  templateUrl: './combat-page.component.html',
+  styleUrl: './combat-page.component.scss',
+})
+export class CombatPageComponent implements OnInit {
+  protected readonly combatStore = inject(CombatStore);
+  private readonly route = inject(ActivatedRoute);
+  private readonly router = inject(Router);
+
+  ngOnInit(): void {
+    this.loadFromRoute();
+  }
+
+  protected attack(): void {
+    void this.combatStore.attack();
+  }
+
+  protected retry(): void {
+    this.loadFromRoute();
+  }
+
+  protected goToHunt(): void {
+    void this.router.navigate(['/hunt']);
+  }
+
+  protected readonly playerSprite = PLAYER_SPRITE;
+  protected readonly playerIcon = PLAYER_ICON;
+
+  protected monsterSprite(monsterKey: string, artworkPath: string): string {
+    return combatMonsterSpritePath(monsterKey) ?? runtimeMonsterArtworkPath(artworkPath) ?? artworkPath;
+  }
+
+  protected monsterIcon(monsterKey: string, artworkPath: string): string {
+    return combatMonsterIconPath(monsterKey) ?? runtimeMonsterArtworkPath(artworkPath) ?? artworkPath;
+  }
+
+  protected playerHpPercent(): number {
+    const combat = this.combatStore.combat();
+    return combat ? (combat.player.currentHp / combat.player.maxHp) * 100 : 0;
+  }
+
+  protected monsterHpPercent(): number {
+    const combat = this.combatStore.combat();
+    return combat ? (combat.monster.currentHp / combat.monster.maxHp) * 100 : 0;
+  }
+
+  protected logRounds(): CombatLogRound[] {
+    const combat = this.combatStore.combat();
+    if (!combat) {
+      return [];
+    }
+
+    const rounds = new Map<number, CombatEvent[]>();
+    for (const event of combat.events) {
+      const events = rounds.get(event.round) ?? [];
+      events.push(event);
+      rounds.set(event.round, events);
+    }
+
+    return [...rounds.entries()].sort(([a], [b]) => a - b).map(([round, events]) => ({ round, events }));
+  }
+
+  protected formatEvent(event: CombatEvent): string {
+    const combat = this.combatStore.combat();
+    const playerName = combat?.player.name ?? 'Du';
+    const monsterName = combat?.monster.name ?? 'Der Gegner';
+
+    if (event.type === 'DAMAGE') {
+      const attacker = event.source === 'PLAYER' ? playerName : monsterName;
+      const defender = event.target === 'PLAYER' ? playerName : monsterName;
+      return `${attacker} trifft ${defender} für ${event.amount} Schaden.`;
+    }
+
+    if (event.type === 'COMBAT_WON') {
+      return `${monsterName} wurde besiegt.`;
+    }
+
+    return `${playerName} wurde im Kampf besiegt.`;
+  }
+
+  private loadFromRoute(): void {
+    const combatId = this.route.snapshot.paramMap.get('combatId');
+    if (combatId) {
+      void this.combatStore.loadCombat(combatId);
+    }
+  }
+}

apps/web/src/app/features/combat/combat-placeholder-page.component.ts

@@ -1,72 +0,0 @@
-import { Component, inject } from '@angular/core';
-import { ActivatedRoute } from '@angular/router';
-
-@Component({
-  selector: 'app-combat-placeholder-page',
-  template: `
-    <section class="combat-placeholder" aria-label="Kampfvorbereitung">
-      <span class="combat-placeholder__eyebrow">KAMPF</span>
-      <h2>Vorbereitung auf den Kampf</h2>
-      <p>
-        Die Klinge ist gezogen, der Gegner steht bereit – doch das eigentliche Gefecht liegt noch
-        vor dir. Diese Ansicht ist ein Zwischenhalt auf dem Weg in den Kampf, der in einem
-        späteren Schritt folgt.
-      </p>
-      @if (encounterId) {
-        <p class="combat-placeholder__id" data-encounter-id>
-          Vorbereitung auf den Kampf gegen Begegnung {{ encounterId }}…
-        </p>
-      }
-    </section>
-  `,
-  styles: [
-    `
-      :host {
-        display: block;
-      }
-
-      .combat-placeholder {
-        display: grid;
-        gap: var(--ar-space-3);
-        max-inline-size: 40rem;
-        margin: var(--ar-space-6) auto;
-        padding: var(--ar-space-5);
-        border: 1px solid var(--ar-border);
-        background: var(--ar-panel);
-        box-shadow: var(--ar-shadow-raised);
-        text-align: center;
-      }
-
-      .combat-placeholder__eyebrow {
-        color: var(--ar-gold);
-        font-size: var(--ar-font-sm);
-        letter-spacing: 0.14em;
-        text-transform: uppercase;
-      }
-
-      .combat-placeholder h2 {
-        margin: 0;
-        font-family: Georgia, 'Times New Roman', serif;
-        font-size: 1.6rem;
-        font-weight: 400;
-      }
-
-      .combat-placeholder p {
-        margin: 0;
-        color: var(--ar-text-muted);
-        line-height: 1.55;
-      }
-
-      .combat-placeholder__id {
-        color: var(--ar-text-muted);
-        font-size: var(--ar-font-sm);
-        font-style: italic;
-      }
-    `,
-  ],
-})
-export class CombatPlaceholderPageComponent {
-  private readonly route = inject(ActivatedRoute);
-
-  protected readonly encounterId = this.route.snapshot.queryParamMap.get('encounterId');
-}

apps/web/src/app/features/combat/combat.store.spec.ts

@@ -0,0 +1,161 @@
+import { HttpErrorResponse } from '@angular/common/http';
+import { TestBed } from '@angular/core/testing';
+import { from, of, throwError } from 'rxjs';
+import { vi } from 'vitest';
+import type { Combat } from '../../core/api/game-api.models';
+import { GameApiService } from '../../core/api/game-api.service';
+import { CombatStore } from './combat.store';
+
+const startedCombat: Combat = {
+  id: 'combat-1',
+  status: 'ACTIVE',
+  round: 1,
+  player: { name: 'Aric Duskwalker', maxHp: 100, currentHp: 100 },
+  monster: {
+    key: 'ash-rat',
+    name: 'Aschenratte',
+    level: 1,
+    maxHp: 45,
+    currentHp: 45,
+    artworkPath: '/images/monsters/ash-rat.png',
+  },
+  events: [],
+};
+
+const afterAttack: Combat = {
+  ...startedCombat,
+  round: 2,
+  player: { ...startedCombat.player, currentHp: 95 },
+  monster: { ...startedCombat.monster, currentHp: 31 },
+  events: [
+    { round: 1, sequence: 1, type: 'DAMAGE', source: 'PLAYER', target: 'MONSTER', amount: 14 },
+    { round: 1, sequence: 2, type: 'DAMAGE', source: 'MONSTER', target: 'PLAYER', amount: 5 },
+  ],
+};
+
+describe('CombatStore', () => {
+  let api: {
+    startCombat: ReturnType<typeof vi.fn>;
+    getCombat: ReturnType<typeof vi.fn>;
+    performCombatAction: ReturnType<typeof vi.fn>;
+  };
+  let store: CombatStore;
+
+  beforeEach(() => {
+    api = {
+      startCombat: vi.fn(() => of(startedCombat)),
+      getCombat: vi.fn(() => of(startedCombat)),
+      performCombatAction: vi.fn(() => of(afterAttack)),
+    };
+
+    TestBed.configureTestingModule({
+      providers: [CombatStore, { provide: GameApiService, useValue: api }],
+    });
+    store = TestBed.inject(CombatStore);
+  });
+
+  it('starts a combat and stores it', async () => {
+    await store.startCombat('encounter-1');
+
+    expect(api.startCombat).toHaveBeenCalledWith('encounter-1');
+    expect(store.combat()).toEqual(startedCombat);
+    expect(store.error()).toBeNull();
+  });
+
+  it('clears any previous combat and reports the mapped error when starting fails', async () => {
+    api.startCombat.mockReturnValue(
+      throwError(
+        () =>
+          new HttpErrorResponse({
+            status: 409,
+            error: { statusCode: 409, code: 'COMBAT_ALREADY_ACTIVE', message: 'Active.' },
+          }),
+      ),
+    );
+
+    await store.startCombat('encounter-1');
+
+    expect(store.combat()).toBeNull();
+    expect(store.error()).toBe('Du befindest dich bereits in einem Kampf.');
+  });
+
+  it('loads a combat by id', async () => {
+    await store.loadCombat('combat-1');
+
+    expect(api.getCombat).toHaveBeenCalledWith('combat-1');
+    expect(store.combat()).toEqual(startedCombat);
+  });
+
+  it('reports the mapped error when loading an unknown combat', async () => {
+    api.getCombat.mockReturnValue(
+      throwError(
+        () =>
+          new HttpErrorResponse({
+            status: 404,
+            error: { statusCode: 404, code: 'COMBAT_NOT_FOUND', message: 'Not found.' },
+          }),
+      ),
+    );
+
+    await store.loadCombat('unknown');
+
+    expect(store.error()).toBe('Dieser Kampf wurde nicht gefunden.');
+  });
+
+  it('sends only the ATTACK action and replaces combat with the server response', async () => {
+    await store.startCombat('encounter-1');
+
+    await store.attack();
+
+    expect(api.performCombatAction).toHaveBeenCalledWith('combat-1', 'ATTACK');
+    expect(store.combat()).toEqual(afterAttack);
+  });
+
+  it('does nothing when attacking without a loaded combat', async () => {
+    await store.attack();
+
+    expect(api.performCombatAction).not.toHaveBeenCalled();
+  });
+
+  it('ignores a second attack while the first is still pending', async () => {
+    await store.startCombat('encounter-1');
+    let resolveAttack!: (value: Combat) => void;
+    api.performCombatAction.mockReturnValue(
+      from(
+        new Promise<Combat>((resolve) => {
+          resolveAttack = resolve;
+        }),
+      ),
+    );
+
+    const first = store.attack();
+    expect(store.actionPending()).toBe(true);
+    const second = store.attack();
+
+    resolveAttack(afterAttack);
+    await Promise.all([first, second]);
+
+    expect(api.performCombatAction).toHaveBeenCalledOnce();
+  });
+
+  it('clears actionPending after a failed attack and keeps the previous combat state', async () => {
+    await store.startCombat('encounter-1');
+    api.performCombatAction.mockReturnValue(throwError(() => new Error('Netzwerkfehler')));
+
+    await store.attack();
+
+    expect(store.actionPending()).toBe(false);
+    expect(store.combat()).toEqual(startedCombat);
+    expect(store.error()).toBe('Netzwerkfehler');
+  });
+
+  it('clears the error message', async () => {
+    api.startCombat.mockReturnValue(throwError(() => new Error('x')));
+    await store.startCombat('encounter-1');
+    expect(store.error()).not.toBeNull();
+
+    store.clearError();
+
+    expect(store.error()).toBeNull();
+  });
+});

apps/web/src/app/features/combat/combat.store.ts

@@ -0,0 +1,95 @@
+import { HttpErrorResponse } from '@angular/common/http';
+import { Injectable, signal } from '@angular/core';
+import { firstValueFrom } from 'rxjs';
+import { Combat } from '../../core/api/game-api.models';
+import { GameApiService } from '../../core/api/game-api.service';
+
+const GENERIC_ERROR_MESSAGE = 'Der Kampf konnte nicht geladen werden.';
+
+// Mirrors the combat error codes returned by the combat endpoints.
+// Unknown/missing codes fall back to `GENERIC_ERROR_MESSAGE`.
+const COMBAT_ERROR_MESSAGES: Readonly<Record<string, string>> = {
+  HUNT_ENCOUNTER_NOT_FOUND: 'Diese Begegnung wurde nicht gefunden.',
+  HUNT_ENCOUNTER_ALREADY_CONSUMED: 'Diese Begegnung wurde bereits genutzt.',
+  INVALID_HUNT_ENCOUNTER: 'Diese Begegnung ist nicht mehr gültig.',
+  CHARACTER_TRAVELLING: 'Du kannst nicht kämpfen, während du unterwegs bist.',
+  COMBAT_ALREADY_ACTIVE: 'Du befindest dich bereits in einem Kampf.',
+  COMBAT_NOT_FOUND: 'Dieser Kampf wurde nicht gefunden.',
+  COMBAT_ALREADY_FINISHED: 'Dieser Kampf ist bereits beendet.',
+};
+
+@Injectable({ providedIn: 'root' })
+export class CombatStore {
+  private readonly combatState = signal<Combat | null>(null);
+  private readonly loadingState = signal(false);
+  private readonly actionPendingState = signal(false);
+  private readonly errorState = signal<string | null>(null);
+
+  readonly combat = this.combatState.asReadonly();
+  readonly loading = this.loadingState.asReadonly();
+  readonly actionPending = this.actionPendingState.asReadonly();
+  readonly error = this.errorState.asReadonly();
+
+  constructor(private readonly api: GameApiService) {}
+
+  async startCombat(encounterId: string): Promise<void> {
+    this.loadingState.set(true);
+    this.errorState.set(null);
+
+    try {
+      const combat = await firstValueFrom(this.api.startCombat(encounterId));
+      this.combatState.set(combat);
+    } catch (error) {
+      this.combatState.set(null);
+      this.errorState.set(this.toErrorMessage(error));
+    } finally {
+      this.loadingState.set(false);
+    }
+  }
+
+  async loadCombat(combatId: string): Promise<void> {
+    this.loadingState.set(true);
+    this.errorState.set(null);
+
+    try {
+      const combat = await firstValueFrom(this.api.getCombat(combatId));
+      this.combatState.set(combat);
+    } catch (error) {
+      this.errorState.set(this.toErrorMessage(error));
+    } finally {
+      this.loadingState.set(false);
+    }
+  }
+
+  async attack(): Promise<void> {
+    const combat = this.combatState();
+    if (!combat || this.actionPendingState()) {
+      return;
+    }
+
+    this.actionPendingState.set(true);
+    this.errorState.set(null);
+
+    try {
+      const updated = await firstValueFrom(this.api.performCombatAction(combat.id, 'ATTACK'));
+      this.combatState.set(updated);
+    } catch (error) {
+      this.errorState.set(this.toErrorMessage(error));
+    } finally {
+      this.actionPendingState.set(false);
+    }
+  }
+
+  clearError(): void {
+    this.errorState.set(null);
+  }
+
+  private toErrorMessage(error: unknown): string {
+    if (error instanceof HttpErrorResponse) {
+      const code = (error.error as { code?: string } | null)?.code;
+      return (code && COMBAT_ERROR_MESSAGES[code]) || GENERIC_ERROR_MESSAGE;
+    }
+
+    return error instanceof Error ? error.message : GENERIC_ERROR_MESSAGE;
+  }
+}

apps/web/src/app/features/hunting/encounter-card/encounter-card.component.ts

@@ -1,12 +1,8 @@
 import { Component, EventEmitter, Input, Output } from '@angular/core';
 import { HuntEncounter } from '../../../core/api/game-api.models';
+import { runtimeMonsterArtworkPath } from '../../../shared/monster-artwork';
 import { DangerBadgeComponent } from '../../../shared/danger-badge/danger-badge.component';
 
-const runtimeArtworkPaths: Readonly<Record<string, string>> = {
-  '/images/monsters/ash-rat.png': '/images/monsters/runtime/ash-rat-560.jpg',
-  '/images/monsters/road-bandit.png': '/images/monsters/runtime/road-bandit-560.jpg',
-};
-
 @Component({
   selector: 'app-encounter-card',
   imports: [DangerBadgeComponent],
@@ -22,6 +18,6 @@ export class EncounterCardComponent {
   }
 
   protected runtimeArtworkPath(artworkPath: string): string | undefined {
-    return runtimeArtworkPaths[artworkPath];
+    return runtimeMonsterArtworkPath(artworkPath);
   }
 }

apps/web/src/app/features/hunting/hunt-page/hunt-page.component.html

@@ -64,4 +64,11 @@
       <button type="button" data-hunt-retry (click)="retry()">Erneut versuchen</button>
     </section>
   }
+
+  @if (combatStore.error(); as combatError) {
+    <section class="hunt-page__error" role="alert">
+      <p>{{ combatError }}</p>
+      <button type="button" data-hunt-combat-dismiss (click)="dismissCombatError()">Schließen</button>
+    </section>
+  }
 </section>

apps/web/src/app/features/hunting/hunt-page/hunt-page.component.spec.ts

@@ -1,8 +1,10 @@
+// apps/web/src/app/features/hunting/hunt-page/hunt-page.component.spec.ts
 import { signal } from '@angular/core';
 import { TestBed } from '@angular/core/testing';
 import { Router, provideRouter } from '@angular/router';
 import { vi } from 'vitest';
-import type { CurrentLocationResponse, HuntResult } from '../../../core/api/game-api.models';
+import type { Combat, CurrentLocationResponse, HuntResult } from '../../../core/api/game-api.models';
+import { CombatStore } from '../../combat/combat.store';
 import { WorldStore } from '../../world/world.store';
 import { HuntingStore } from '../hunting.store';
 import { HuntPageComponent } from './hunt-page.component';
@@ -42,12 +44,7 @@ const threeEncounterHunt: HuntResult = {
   encounters: [
     {
       id: 'encounter-1',
-      monster: {
-        key: 'ash-rat',
-        name: 'Aschenratte',
-        level: 1,
-        artworkPath: '/images/enemies/AshRat.png',
-      },
+      monster: { key: 'ash-rat', name: 'Aschenratte', level: 1, artworkPath: '/images/enemies/AshRat.png' },
       dangerRating: 'WEAK',
     },
     {
@@ -62,17 +59,28 @@ const threeEncounterHunt: HuntResult = {
     },
     {
       id: 'encounter-3',
-      monster: {
-        key: 'ash-rat',
-        name: 'Aschenratte',
-        level: 1,
-        artworkPath: '/images/enemies/AshRat.png',
-      },
+      monster: { key: 'ash-rat', name: 'Aschenratte', level: 1, artworkPath: '/images/enemies/AshRat.png' },
       dangerRating: 'WEAK',
     },
   ],
 };
 
+const startedCombat: Combat = {
+  id: 'combat-2',
+  status: 'ACTIVE',
+  round: 1,
+  player: { name: 'Aric Duskwalker', maxHp: 100, currentHp: 100 },
+  monster: {
+    key: 'road-bandit',
+    name: 'Straßenräuber',
+    level: 3,
+    maxHp: 75,
+    currentHp: 75,
+    artworkPath: '/images/enemies/RoadBandit.png',
+  },
+  events: [],
+};
+
 describe('HuntPageComponent', () => {
   let worldStore: {
     currentLocation: ReturnType<typeof signal<CurrentLocationResponse | null>>;
@@ -87,6 +95,12 @@ describe('HuntPageComponent', () => {
     refreshHunt: ReturnType<typeof vi.fn>;
     selectEncounter: ReturnType<typeof vi.fn>;
   };
+  let combatStore: {
+    combat: ReturnType<typeof signal<Combat | null>>;
+    error: ReturnType<typeof signal<string | null>>;
+    startCombat: ReturnType<typeof vi.fn>;
+    clearError: ReturnType<typeof vi.fn>;
+  };
   let router: Router;
 
   async function setup(location: CurrentLocationResponse | null, hunt: HuntResult | null = null) {
@@ -101,6 +115,12 @@ describe('HuntPageComponent', () => {
       refreshHunt: vi.fn(() => Promise.resolve()),
       selectEncounter: vi.fn(),
     };
+    combatStore = {
+      combat: signal<Combat | null>(null),
+      error: signal<string | null>(null),
+      startCombat: vi.fn(() => Promise.resolve()),
+      clearError: vi.fn(),
+    };
 
     await TestBed.configureTestingModule({
       imports: [HuntPageComponent],
@@ -108,6 +128,7 @@ describe('HuntPageComponent', () => {
         provideRouter([]),
         { provide: WorldStore, useValue: worldStore },
         { provide: HuntingStore, useValue: huntingStore },
+        { provide: CombatStore, useValue: combatStore },
       ],
     }).compileComponents();
 
@@ -124,9 +145,7 @@ describe('HuntPageComponent', () => {
     const element = fixture.nativeElement as HTMLElement;
 
     expect(element.textContent).toContain('Keine Jagd verfügbar');
-    expect(element.textContent).toContain(
-      'Am Südtor von Graufurt gibt es keine regulären Jagdgebiete.',
-    );
+    expect(element.textContent).toContain('Am Südtor von Graufurt gibt es keine regulären Jagdgebiete.');
     expect(
       Array.from(element.querySelectorAll('button')).some(
         (button) => button.textContent?.trim() === 'Jagd beginnen',
@@ -171,8 +190,11 @@ describe('HuntPageComponent', () => {
     expect(huntingStore.refreshHunt).toHaveBeenCalledOnce();
   });
 
-  it('navigates to /combat/new with the encounter id (not the monster key) when Angreifen is clicked', async () => {
+  it('starts a real combat from the encounter id (not the monster key) and navigates to /combat/:combatId', async () => {
     const fixture = await setup(burnedRoad, threeEncounterHunt);
+    combatStore.startCombat.mockImplementation(async () => {
+      combatStore.combat.set(startedCombat);
+    });
     const element = fixture.nativeElement as HTMLElement;
 
     const attackButtons = Array.from(element.querySelectorAll('button')).filter(
@@ -181,14 +203,43 @@ describe('HuntPageComponent', () => {
     expect(attackButtons.length).toBe(3);
 
     attackButtons[1].click();
+    await Promise.resolve();
+    await Promise.resolve();
 
-    expect(huntingStore.selectEncounter).toHaveBeenCalledWith('encounter-2');
-    expect(router.navigate).toHaveBeenCalledWith(['/combat/new'], {
-      queryParams: { encounterId: 'encounter-2' },
-    });
-    expect(router.navigate).not.toHaveBeenCalledWith(['/combat/new'], {
-      queryParams: { encounterId: 'road-bandit' },
-    });
+    expect(combatStore.startCombat).toHaveBeenCalledWith('encounter-2');
+    expect(combatStore.startCombat).not.toHaveBeenCalledWith('road-bandit');
+    expect(router.navigate).toHaveBeenCalledWith(['/combat', 'combat-2']);
+  });
+
+  it('does not navigate when starting the combat fails', async () => {
+    const fixture = await setup(burnedRoad, threeEncounterHunt);
+    const element = fixture.nativeElement as HTMLElement;
+
+    const attackButtons = Array.from(element.querySelectorAll('button')).filter(
+      (button) => button.textContent?.trim() === 'Angreifen',
+    );
+    attackButtons[0].click();
+    await Promise.resolve();
+    await Promise.resolve();
+
+    expect(combatStore.startCombat).toHaveBeenCalledWith('encounter-1');
+    expect(router.navigate).not.toHaveBeenCalledWith(['/combat', expect.anything()]);
+  });
+
+  it('shows a combat-start error and dismisses it', async () => {
+    const fixture = await setup(burnedRoad, threeEncounterHunt);
+    combatStore.error.set('Du befindest dich bereits in einem Kampf.');
+    fixture.detectChanges();
+
+    const element = fixture.nativeElement as HTMLElement;
+    const alerts = Array.from(element.querySelectorAll('[role="alert"]'));
+    expect(alerts.some((alert) => alert.textContent?.includes('Du befindest dich bereits in einem Kampf.'))).toBe(
+      true,
+    );
+
+    element.querySelector<HTMLButtonElement>('[data-hunt-combat-dismiss]')?.click();
+
+    expect(combatStore.clearError).toHaveBeenCalledOnce();
   });
 
   it('does not trigger a hunt automatically on page entry', async () => {

apps/web/src/app/features/hunting/hunt-page/hunt-page.component.ts

@@ -1,8 +1,9 @@
 import { Component, OnInit, inject } from '@angular/core';
 import { Router } from '@angular/router';
+import { CombatStore } from '../../combat/combat.store';
+import { WorldStore } from '../../world/world.store';
 import { EncounterCardComponent } from '../encounter-card/encounter-card.component';
 import { HuntingStore } from '../hunting.store';
-import { WorldStore } from '../../world/world.store';
 
 @Component({
   selector: 'app-hunt-page',
@@ -13,6 +14,7 @@ import { WorldStore } from '../../world/world.store';
 export class HuntPageComponent implements OnInit {
   protected readonly worldStore = inject(WorldStore);
   protected readonly huntingStore = inject(HuntingStore);
+  protected readonly combatStore = inject(CombatStore);
   private readonly router = inject(Router);
 
   ngOnInit(): void {
@@ -41,8 +43,15 @@ export class HuntPageComponent implements OnInit {
     void this.router.navigate(['/world']);
   }
 
-  protected onAttack(encounterId: string): void {
-    this.huntingStore.selectEncounter(encounterId);
-    void this.router.navigate(['/combat/new'], { queryParams: { encounterId } });
+  protected async onAttack(encounterId: string): Promise<void> {
+    await this.combatStore.startCombat(encounterId);
+    const combat = this.combatStore.combat();
+    if (combat) {
+      void this.router.navigate(['/combat', combat.id]);
+    }
+  }
+
+  protected dismissCombatError(): void {
+    this.combatStore.clearError();
   }
 }

apps/web/src/app/shared/monster-artwork.spec.ts

@@ -0,0 +1,13 @@
+import { runtimeMonsterArtworkPath } from './monster-artwork';
+
+describe('runtimeMonsterArtworkPath', () => {
+  it('returns the optimized JPEG derivative for a known monster artwork path', () => {
+    expect(runtimeMonsterArtworkPath('/images/monsters/ash-rat.png')).toBe(
+      '/images/monsters/runtime/ash-rat-560.jpg',
+    );
+  });
+
+  it('returns undefined for an artwork path with no runtime derivative', () => {
+    expect(runtimeMonsterArtworkPath('/images/enemies/Dawnwolf.png')).toBeUndefined();
+  });
+});

apps/web/src/app/shared/monster-artwork.ts

@@ -0,0 +1,26 @@
+const RUNTIME_MONSTER_ARTWORK: Readonly<Record<string, string>> = {
+  '/images/monsters/ash-rat.png': '/images/monsters/runtime/ash-rat-560.jpg',
+  '/images/monsters/road-bandit.png': '/images/monsters/runtime/road-bandit-560.jpg',
+};
+
+export function runtimeMonsterArtworkPath(artworkPath: string): string | undefined {
+  return RUNTIME_MONSTER_ARTWORK[artworkPath];
+}
+
+const COMBAT_MONSTER_SPRITE: Readonly<Record<string, string>> = {
+  'ash-rat': '/images/combat/sprites/ash-rat-760.png',
+  'road-bandit': '/images/combat/sprites/road-bandit-620.png',
+};
+
+const COMBAT_MONSTER_ICON: Readonly<Record<string, string>> = {
+  'ash-rat': '/images/combat/icons/ash-rat-128.png',
+  'road-bandit': '/images/combat/icons/road-bandit-128.png',
+};
+
+export function combatMonsterSpritePath(monsterKey: string): string | undefined {
+  return COMBAT_MONSTER_SPRITE[monsterKey];
+}
+
+export function combatMonsterIconPath(monsterKey: string): string | undefined {
+  return COMBAT_MONSTER_ICON[monsterKey];
+}