diff --git a/packages/logic/src/domain/entities.ts b/packages/logic/src/domain/entities.ts
new file mode 100644
index 0000000..df279e1
--- /dev/null
+++ b/packages/logic/src/domain/entities.ts
@@ -0,0 +1,80 @@
+// 도메인 기본 엔티티: 서비스/DB에 의존하지 않는 공통 모델.
+
+export type GeneralId = number;
+export type CityId = number;
+export type NationId = number;
+
+export type ColorCode = string;
+
+export interface StatBlock {
+    leadership: number;
+    strength: number;
+    intelligence: number;
+}
+
+export type TriggerValue = boolean | number | string;
+
+export interface GeneralTriggerState {
+    // Trigger 시스템에서 사용하는 확장 슬롯.
+    flags: Record<string, boolean>;
+    counters: Record<string, number>;
+    modifiers: Record<string, number>;
+    meta: Record<string, TriggerValue>;
+}
+
+export interface General<TriggerState extends GeneralTriggerState = GeneralTriggerState> {
+    id: GeneralId;
+    name: string;
+    nationId: NationId;
+    cityId: CityId;
+    troopId: number;
+    stats: StatBlock;
+    experience: number;
+    dedication: number;
+    officerLevel: number;
+    injury: number;
+    gold: number;
+    rice: number;
+    crew: number;
+    train: number;
+    age: number;
+    npcState: number;
+    triggerState: TriggerState;
+    meta: Record<string, TriggerValue>;
+}
+
+export interface City {
+    id: CityId;
+    name: string;
+    nationId: NationId;
+    level: number;
+    population: number;
+    populationMax: number;
+    agriculture: number;
+    agricultureMax: number;
+    commerce: number;
+    commerceMax: number;
+    security: number;
+    securityMax: number;
+    supplyState: number;
+    frontState: number;
+    defence: number;
+    defenceMax: number;
+    wall: number;
+    wallMax: number;
+    meta: Record<string, TriggerValue>;
+}
+
+export interface Nation {
+    id: NationId;
+    name: string;
+    color: ColorCode;
+    capitalCityId: CityId | null;
+    chiefGeneralId: GeneralId | null;
+    gold: number;
+    rice: number;
+    power: number;
+    level: number;
+    typeCode: string;
+    meta: Record<string, TriggerValue>;
+}
diff --git a/packages/logic/src/index.ts b/packages/logic/src/index.ts
index cb0ff5c..6d6cccb 100644
--- a/packages/logic/src/index.ts
+++ b/packages/logic/src/index.ts
@@ -1 +1,2 @@
-export {};
+export * from './domain/entities';
+export * from './ports/world';
diff --git a/packages/logic/src/ports/world.ts b/packages/logic/src/ports/world.ts
new file mode 100644
index 0000000..bb2c6d5
--- /dev/null
+++ b/packages/logic/src/ports/world.ts
@@ -0,0 +1,55 @@
+// 도메인 로직이 DB에 직접 접근하지 않도록 하는 인터페이스.
+
+import type {
+    City,
+    CityId,
+    General,
+    GeneralId,
+    Nation,
+    NationId,
+} from '../domain/entities';
+
+export interface GeneralRepository<GeneralType extends General = General> {
+    getById(id: GeneralId): Promise<GeneralType | null>;
+    listByNation(nationId: NationId): Promise<GeneralType[]>;
+    save(general: GeneralType): Promise<void>;
+}
+
+export interface CityRepository<CityType extends City = City> {
+    getById(id: CityId): Promise<CityType | null>;
+    listByNation(nationId: NationId): Promise<CityType[]>;
+    save(city: CityType): Promise<void>;
+}
+
+export interface NationRepository<NationType extends Nation = Nation> {
+    getById(id: NationId): Promise<NationType | null>;
+    listAll(): Promise<NationType[]>;
+    save(nation: NationType): Promise<void>;
+}
+
+export interface WorldStateReader<
+    GeneralType extends General = General,
+    CityType extends City = City,
+    NationType extends Nation = Nation
+> {
+    getGeneralById(id: GeneralId): Promise<GeneralType | null>;
+    getCityById(id: CityId): Promise<CityType | null>;
+    getNationById(id: NationId): Promise<NationType | null>;
+}
+
+export interface WorldStateWriter<
+    GeneralType extends General = General,
+    CityType extends City = City,
+    NationType extends Nation = Nation
+> {
+    saveGeneral(general: GeneralType): Promise<void>;
+    saveCity(city: CityType): Promise<void>;
+    saveNation(nation: NationType): Promise<void>;
+}
+
+export interface WorldStateRepository<
+    GeneralType extends General = General,
+    CityType extends City = City,
+    NationType extends Nation = Nation
+> extends WorldStateReader<GeneralType, CityType, NationType>,
+        WorldStateWriter<GeneralType, CityType, NationType> {}