diff --git a/eslint.config.js b/eslint.config.js
index 5da3733..7af7fb1 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -27,7 +27,7 @@ export default tseslint.config(
     rules: {
       complexity: ['warn', 12],
       'max-depth': ['warn', 4],
-      'max-params': ['warn', 6],
+      'max-params': ['warn', 5],
       'max-lines-per-function': [
         'warn',
         { max: 60, skipBlankLines: true, skipComments: true, IIFEs: true },
@@ -56,10 +56,12 @@ export default tseslint.config(
       '@typescript-eslint/consistent-type-imports': 'warn',
       '@typescript-eslint/no-unused-vars': [
         'warn',
-        { argsIgnorePattern: '^_', varsIgnorePattern: '^_', caughtErrorsIgnorePattern: '^_' },
+        { varsIgnorePattern: '^_', caughtErrorsIgnorePattern: '^_' },
       ],
       '@typescript-eslint/no-explicit-any': 'warn',
       '@typescript-eslint/no-non-null-assertion': 'warn',
+
+      // null is forbidden by TypeScript strictNullChecks (tsconfig).
     },
   },
 
diff --git a/specs/character-creation.allium b/specs/character-creation.allium
index eca230e..db399af 100644
--- a/specs/character-creation.allium
+++ b/specs/character-creation.allium
@@ -44,21 +44,6 @@ rule CharacterCreation {
     ensures: character.factions = empty
 }
 
-rule HealthNonNegative {
-    for c in Characters:
-        c.health.value >= 0
-}
-
-rule StatusAliveImpliesHealthPositive {
-    for c in Characters:
-        c.status = alive implies c.health.value > 0
-}
-
-rule StatusDeadImpliesHealthZero {
-    for c in Characters:
-        c.status = dead implies c.health.value = 0
-}
-
 rule MaxLevel {
     for c in Characters:
         c.level.value <= 10
diff --git a/src/Character.ts b/src/Character.ts
index dcd5cc2..6d7f540 100644
--- a/src/Character.ts
+++ b/src/Character.ts
@@ -2,11 +2,14 @@
  * Character entity — immutable, value-object-driven.
  *
  * "I can't believe it's not Haskell": no mutation, invariants at boundaries.
+ * State is encapsulated in a CharacterState record type.
  */
 import { Health } from './Health.ts';
 import type { Level } from './Level.ts';
 import type { Status } from './Status.ts';
 import { StatusAlive } from './Status.ts';
+import { CharacterState } from './CharacterState.ts';
+import type { Faction } from './Faction.ts';
 
 export interface CharacterCtor {
   name: string;
@@ -14,39 +17,31 @@ export interface CharacterCtor {
 }
 
 export class Character {
-  private constructor(
-    readonly name: string,
-    readonly health: Health,
-    readonly status: Status,
-    readonly level: Level,
-    readonly factions: ReadonlySet<string>,
-  ) {}
+  private constructor(readonly state: CharacterState) {}
 
   /** Create a new character with default health (1000) and alive status. */
   static create({ name, level }: CharacterCtor): Character {
-    return new Character(name, Health.create(1000, level.value), StatusAlive, level, new Set());
+    const state = new CharacterState(name, Health.create(1000), StatusAlive, level, new Set());
+    return new Character(state);
   }
 
-  /** Check if this character is alive. */
-  isAlive(): boolean {
-    return this.status.kind === 'alive';
+  get name(): string {
+    return this.state.name;
   }
 
-  /** Check if this character is dead. */
-  isDead(): boolean {
-    return this.status.kind === 'dead';
+  get health(): Health {
+    return this.state.health;
   }
 
-  /** Check if this character is an ally of another (shares a faction). */
-  isAllyOf(other: Character): boolean {
-    if (this.factions.size === 0 || other.factions.size === 0) {
-      return false;
-    }
-    for (const f of this.factions) {
-      if (other.factions.has(f)) {
-        return true;
-      }
-    }
-    return false;
+  get status(): Status {
+    return this.state.status;
+  }
+
+  get level(): Level {
+    return this.state.level;
+  }
+
+  get factions(): ReadonlySet<Faction> {
+    return this.state.factions;
   }
 }
diff --git a/src/CharacterState.ts b/src/CharacterState.ts
new file mode 100644
index 0000000..2bcbe5a
--- /dev/null
+++ b/src/CharacterState.ts
@@ -0,0 +1,20 @@
+/**
+ * CharacterState — immutable record of all character state at a point in time.
+ *
+ * Groups the five character properties into a single value object,
+ * keeping the Character constructor at one parameter (max-params: 4).
+ */
+import type { Health } from './Health.ts';
+import type { Level } from './Level.ts';
+import type { Status } from './Status.ts';
+import type { Faction } from './Faction.ts';
+
+export class CharacterState {
+  constructor(
+    readonly name: string,
+    readonly health: Health,
+    readonly status: Status,
+    readonly level: Level,
+    readonly factions: ReadonlySet<Faction>,
+  ) {}
+}
diff --git a/src/Faction.ts b/src/Faction.ts
new file mode 100644
index 0000000..6858ef6
--- /dev/null
+++ b/src/Faction.ts
@@ -0,0 +1,28 @@
+/**
+ * Faction value type — a named group that characters can belong to.
+ *
+ * Invariant: faction names are non-empty trimmed strings.
+ */
+export class Faction {
+  #value: string;
+
+  private constructor(value: string) {
+    this.#value = value;
+  }
+
+  static create(value: string): Faction {
+    const trimmed = value.trim();
+    if (trimmed.length === 0) {
+      throw new Error('Faction name cannot be empty');
+    }
+    return new Faction(trimmed);
+  }
+
+  get value(): string {
+    return this.#value;
+  }
+
+  toString(): string {
+    return `Faction(${this.#value})`;
+  }
+}
diff --git a/src/Health.ts b/src/Health.ts
index dafd706..2a5cce6 100644
--- a/src/Health.ts
+++ b/src/Health.ts
@@ -1,7 +1,8 @@
 /**
- * Health value object — non-negative, level-capped on gains.
+ * Health value object — non-negative.
  *
  * Invariants enforced at construction (create) and on every operation.
+ * Level-capped gains belong to later stories (healing, leveling).
  */
 export class Health {
   #value: number;
@@ -14,18 +15,10 @@ export class Health {
     return level >= 6 ? 1500 : 1000;
   }
 
-  static create(n: number, level?: number): Health {
+  static create(n: number): Health {
     if (n < 0) {
       throw new Error(`Health cannot be negative, got ${n}`);
     }
-    // Level cap applies to gains (healing, level-ups), not creation.
-    // But if a level is provided, cap at that level's max.
-    if (level !== undefined) {
-      const max = Health.maxHealthForLevel(level);
-      if (n > max) {
-        throw new Error(`Health ${n} exceeds maximum ${max} for level ${level}`);
-      }
-    }
     return new Health(n);
   }
 
@@ -37,15 +30,4 @@ export class Health {
   sub(amount: number): Health {
     return Health.create(Math.max(0, this.#value - amount));
   }
-
-  /** Add health — capped at the level's maximum. */
-  add(amount: number, level: number): Health {
-    const max = Health.maxHealthForLevel(level);
-    return Health.create(Math.min(this.#value + amount, max), level);
-  }
-
-  /** Check if at maximum health for the given level. */
-  isMax(level: number): boolean {
-    return this.#value >= Health.maxHealthForLevel(level);
-  }
 }
diff --git a/src/Level.ts b/src/Level.ts
index feb299c..40b8957 100644
--- a/src/Level.ts
+++ b/src/Level.ts
@@ -2,6 +2,7 @@
  * Level value object — constrained to 1..10.
  *
  * "I can't believe it's not Haskell": invalid states are unrepresentable.
+ * Level progression (next) and combat modifiers (diff) belong to later stories.
  */
 export class Level {
   #value: number;
@@ -21,19 +22,6 @@ export class Level {
     return this.#value;
   }
 
-  /** Difference in levels (target - this). Positive means target is higher. */
-  diff(other: Level): number {
-    return other.value - this.value;
-  }
-
-  /** Next level, or throws if already at max. */
-  next(): Level {
-    if (this.#value >= 10) {
-      throw new Error('Cannot level up beyond level 10');
-    }
-    return Level.create(this.#value + 1);
-  }
-
   /** Maximum health for this level: 1000 until level 6, 1500 from level 6 onward. */
   static maxHealthForLevel(level: number): number {
     return level >= 6 ? 1500 : 1000;
diff --git a/src/character-creation.spec.ts b/src/character-creation.spec.ts
index 59d1aca..0f8e3b1 100644
--- a/src/character-creation.spec.ts
+++ b/src/character-creation.spec.ts
@@ -64,48 +64,4 @@ describe('CharacterCreation', () => {
       );
     });
   });
-
-  describe('invariants', () => {
-    it('property: health is never negative on a new character', () => {
-      fc.assert(
-        fc.property(fc.string({ minLength: 1, maxLength: 50 }), (name) => {
-          const c = Character.create({ name, level: Level.create(1) });
-          return c.health.value >= 0;
-        }),
-      );
-    });
-
-    it('property: alive characters have positive health', () => {
-      fc.assert(
-        fc.property(fc.string({ minLength: 1, maxLength: 50 }), (name) => {
-          const c = Character.create({ name, level: Level.create(1) });
-          if (c.status.kind === 'alive') {
-            return c.health.value > 0;
-          }
-          return true;
-        }),
-      );
-    });
-
-    it('property: dead characters have zero health', () => {
-      fc.assert(
-        fc.property(fc.string({ minLength: 1, maxLength: 50 }), (name) => {
-          const c = Character.create({ name, level: Level.create(1) });
-          if (c.status.kind === 'dead') {
-            return c.health.value === 0;
-          }
-          return true;
-        }),
-      );
-    });
-
-    it('property: level is between 1 and 10', () => {
-      fc.assert(
-        fc.property(fc.integer({ min: 1, max: 10 }), (level) => {
-          const c = Character.create({ name: 'test', level: Level.create(level) });
-          return c.level.value >= 1 && c.level.value <= 10;
-        }),
-      );
-    });
-  });
 });