diff --git a/scripts/verify-battle-save-normalization.mjs b/scripts/verify-battle-save-normalization.mjs
index bf79005..6e6e922 100644
--- a/scripts/verify-battle-save-normalization.mjs
+++ b/scripts/verify-battle-save-normalization.mjs
@@ -15,9 +15,10 @@ try {
     expectedBattleId: 'first-battle-zhuo-commandery',
     mapWidth: 12,
     mapHeight: 8,
-    validUnitIds: new Set(['liu-bei'])
+    validUnitIds: new Set(['liu-bei', 'guan-yu', 'rebel-1'])
   };
   const validState = createValidBattleSaveState();
+  const patchUnit = (index, patch) => validState.units.map((unit, unitIndex) => (unitIndex === index ? { ...unit, ...patch } : unit));
 
   assert(normalizeBattleSaveSlot(0, 3) === 1, 'Expected slot 0 to normalize to slot 1.');
   assert(normalizeBattleSaveSlot(Number.NaN, 3) === 1, 'Expected NaN slot to normalize to slot 1.');
@@ -35,19 +36,26 @@ try {
     ['invalid activeFaction', { activeFaction: 'neutral' }],
     ['invalid rosterTab', { rosterTab: 'neutral' }],
     ['invalid actedUnitIds', { actedUnitIds: 'liu-bei' }],
+    ['unknown acted unit id', { actedUnitIds: ['ghost-unit'] }],
     ['invalid battleLog', { battleLog: 'hit' }],
     ['invalid attackIntents', { attackIntents: [{ attackerId: 'liu-bei' }] }],
+    ['unknown attack intent unit id', { attackIntents: [{ attackerId: 'liu-bei', targetId: 'ghost-unit' }] }],
     ['invalid units array', { units: {} }],
-    ['invalid unit hp', { units: [{ ...validState.units[0], hp: 99, maxHp: 30 }] }],
-    ['invalid unit x', { units: [{ ...validState.units[0], x: 12 }] }],
-    ['invalid unit direction', { units: [{ ...validState.units[0], direction: 'down' }] }],
-    ['unknown unit id', { units: [{ ...validState.units[0], id: 'ghost-unit' }] }],
-    ['duplicate unit id', { units: [{ ...validState.units[0] }, { ...validState.units[0], x: 2 }] }],
+    ['invalid unit hp', { units: patchUnit(0, { hp: 99, maxHp: 30 }) }],
+    ['invalid unit x', { units: patchUnit(0, { x: 12 }) }],
+    ['invalid unit direction', { units: patchUnit(0, { direction: 'down' }) }],
+    ['unknown unit id', { units: patchUnit(0, { id: 'ghost-unit' }) }],
+    ['duplicate unit id', { units: [validState.units[0], { ...validState.units[0], x: 2 }, validState.units[2]] }],
     ['invalid bonds', { bonds: [{ ...validState.bonds[0], unitIds: ['liu-bei'] }] }],
+    ['unknown bond unit id', { bonds: [{ ...validState.bonds[0], unitIds: ['liu-bei', 'ghost-unit'] }] }],
     ['invalid item stock count', { itemStocks: { 'liu-bei': { bean: -1 } } }],
+    ['unknown item stock unit id', { itemStocks: { 'ghost-unit': { bean: 1 } } }],
     ['invalid buff turns', { battleBuffs: [{ ...validState.battleBuffs[0], turns: 0 }] }],
+    ['unknown buff unit id', { battleBuffs: [{ ...validState.battleBuffs[0], unitId: 'ghost-unit' }] }],
     ['invalid status kind', { battleStatuses: [{ ...validState.battleStatuses[0], kind: 'poison' }] }],
+    ['unknown status unit id', { battleStatuses: [{ ...validState.battleStatuses[0], unitId: 'ghost-unit' }] }],
     ['invalid stats shape', { battleStats: { 'liu-bei': { damageDealt: 10 } } }],
+    ['unknown stats unit id', { battleStats: { 'ghost-unit': validState.battleStats['liu-bei'] } }],
     ['invalid enemy usable keys', { enemyUsableUseKeys: [1] }],
     ['invalid triggered events', { triggeredBattleEvents: [1] }]
   ];
@@ -58,7 +66,7 @@ try {
   });
 
   assert(
-    !isValidBattleSaveState(validState, { ...options, validUnitIds: new Set(['liu-bei', 'guan-yu']) }),
+    !isValidBattleSaveState(validState, { ...options, validUnitIds: new Set(['liu-bei', 'guan-yu', 'rebel-1', 'zhang-fei']) }),
     'Expected save missing a current battle unit to be rejected.'
   );
 
@@ -92,6 +100,32 @@ function createValidBattleSaveState() {
         y: 2,
         direction: 'south',
         equipment: {}
+      },
+      {
+        id: 'guan-yu',
+        level: 2,
+        exp: 5,
+        hp: 32,
+        maxHp: 34,
+        attack: 14,
+        move: 4,
+        x: 2,
+        y: 2,
+        direction: 'south',
+        equipment: {}
+      },
+      {
+        id: 'rebel-1',
+        level: 1,
+        exp: 0,
+        hp: 20,
+        maxHp: 20,
+        attack: 8,
+        move: 3,
+        x: 8,
+        y: 4,
+        direction: 'west',
+        equipment: {}
       }
     ],
     bonds: [
diff --git a/src/game/state/battleSaveState.ts b/src/game/state/battleSaveState.ts
index 9db9b11..3efcb79 100644
--- a/src/game/state/battleSaveState.ts
+++ b/src/game/state/battleSaveState.ts
@@ -116,20 +116,20 @@ export function isValidBattleSaveState(state: unknown, options: BattleSaveValida
   }
 
   if (
-    !isStringArray(state.actedUnitIds) ||
+    !isUnitIdArray(state.actedUnitIds, options) ||
     !isBattleLog(state.battleLog) ||
-    !isAttackIntentArray(state.attackIntents) ||
+    !isAttackIntentArray(state.attackIntents, options) ||
     !areSavedBattleUnitsValid(state.units, options) ||
-    !isBondArray(state.bonds)
+    !isBondArray(state.bonds, options)
   ) {
     return false;
   }
 
   if (
-    !isOptionalNestedCountRecord(state.itemStocks) ||
-    !isOptionalBuffArray(state.battleBuffs) ||
-    !isOptionalStatusArray(state.battleStatuses) ||
-    !isOptionalStatsRecord(state.battleStats) ||
+    !isOptionalNestedCountRecord(state.itemStocks, options) ||
+    !isOptionalBuffArray(state.battleBuffs, options) ||
+    !isOptionalStatusArray(state.battleStatuses, options) ||
+    !isOptionalStatsRecord(state.battleStats, options) ||
     !isOptionalStringArray(state.enemyUsableUseKeys) ||
     !isOptionalStringArray(state.triggeredBattleEvents)
   ) {
@@ -171,6 +171,10 @@ function isStringArray(value: unknown) {
   return Array.isArray(value) && value.every((entry) => typeof entry === 'string');
 }
 
+function isUnitIdArray(value: unknown, options: BattleSaveValidationOptions) {
+  return Array.isArray(value) && value.every((entry) => typeof entry === 'string' && isKnownUnitId(entry, options));
+}
+
 function isOptionalStringArray(value: unknown) {
   return value === undefined || isStringArray(value);
 }
@@ -179,10 +183,17 @@ function isBattleLog(value: unknown) {
   return Array.isArray(value) && value.every((entry) => typeof entry === 'string');
 }
 
-function isAttackIntentArray(value: unknown) {
+function isAttackIntentArray(value: unknown, options: BattleSaveValidationOptions) {
   return (
     Array.isArray(value) &&
-    value.every((intent) => isRecord(intent) && typeof intent.attackerId === 'string' && typeof intent.targetId === 'string')
+    value.every(
+      (intent) =>
+        isRecord(intent) &&
+        typeof intent.attackerId === 'string' &&
+        typeof intent.targetId === 'string' &&
+        isKnownUnitId(intent.attackerId, options) &&
+        isKnownUnitId(intent.targetId, options)
+    )
   );
 }
 
@@ -238,7 +249,7 @@ function isSavedBattleUnitState(value: unknown, options: BattleSaveValidationOpt
   return value.direction === undefined || unitDirections.has(value.direction as UnitDirection);
 }
 
-function isBondArray(value: unknown) {
+function isBondArray(value: unknown, options: BattleSaveValidationOptions) {
   return (
     Array.isArray(value) &&
     value.every(
@@ -247,7 +258,7 @@ function isBondArray(value: unknown) {
         typeof bond.id === 'string' &&
         Array.isArray(bond.unitIds) &&
         bond.unitIds.length === 2 &&
-        bond.unitIds.every((unitId) => typeof unitId === 'string') &&
+        bond.unitIds.every((unitId) => typeof unitId === 'string' && isKnownUnitId(unitId, options)) &&
         isPositiveInteger(bond.level) &&
         isNonNegativeFiniteNumber(bond.exp) &&
         isNonNegativeFiniteNumber(bond.battleExp)
@@ -255,7 +266,7 @@ function isBondArray(value: unknown) {
   );
 }
 
-function isOptionalNestedCountRecord(value: unknown) {
+function isOptionalNestedCountRecord(value: unknown, options: BattleSaveValidationOptions) {
   if (value === undefined) {
     return true;
   }
@@ -264,12 +275,15 @@ function isOptionalNestedCountRecord(value: unknown) {
     return false;
   }
 
-  return Object.values(value).every(
-    (stocks) => isRecord(stocks) && Object.values(stocks).every((count) => Number.isInteger(count) && Number(count) >= 0)
+  return Object.entries(value).every(
+    ([unitId, stocks]) =>
+      isKnownUnitId(unitId, options) &&
+      isRecord(stocks) &&
+      Object.values(stocks).every((count) => Number.isInteger(count) && Number(count) >= 0)
   );
 }
 
-function isOptionalBuffArray(value: unknown) {
+function isOptionalBuffArray(value: unknown, options: BattleSaveValidationOptions) {
   return (
     value === undefined ||
     (Array.isArray(value) &&
@@ -277,6 +291,7 @@ function isOptionalBuffArray(value: unknown) {
         (buff) =>
           isRecord(buff) &&
           typeof buff.unitId === 'string' &&
+          isKnownUnitId(buff.unitId, options) &&
           typeof buff.label === 'string' &&
           isPositiveInteger(buff.turns) &&
           isFiniteNumber(buff.attackBonus) &&
@@ -286,7 +301,7 @@ function isOptionalBuffArray(value: unknown) {
   );
 }
 
-function isOptionalStatusArray(value: unknown) {
+function isOptionalStatusArray(value: unknown, options: BattleSaveValidationOptions) {
   return (
     value === undefined ||
     (Array.isArray(value) &&
@@ -294,6 +309,7 @@ function isOptionalStatusArray(value: unknown) {
         (status) =>
           isRecord(status) &&
           typeof status.unitId === 'string' &&
+          isKnownUnitId(status.unitId, options) &&
           isBattleStatusKind(status.kind) &&
           typeof status.label === 'string' &&
           isPositiveInteger(status.turns) &&
@@ -302,7 +318,7 @@ function isOptionalStatusArray(value: unknown) {
   );
 }
 
-function isOptionalStatsRecord(value: unknown) {
+function isOptionalStatsRecord(value: unknown, options: BattleSaveValidationOptions) {
   if (value === undefined) {
     return true;
   }
@@ -311,8 +327,9 @@ function isOptionalStatsRecord(value: unknown) {
     return false;
   }
 
-  return Object.values(value).every(
-    (stats) =>
+  return Object.entries(value).every(
+    ([unitId, stats]) =>
+      isKnownUnitId(unitId, options) &&
       isRecord(stats) &&
       isNonNegativeFiniteNumber(stats.damageDealt) &&
       isNonNegativeFiniteNumber(stats.damageTaken) &&
@@ -321,3 +338,7 @@ function isOptionalStatsRecord(value: unknown) {
       isNonNegativeFiniteNumber(stats.support)
   );
 }
+
+function isKnownUnitId(unitId: string, options: BattleSaveValidationOptions) {
+  return !options.validUnitIds || options.validUnitIds.has(unitId);
+}