diff --git a/Documentations/COMPLETE_GAME_WORKFLOW.md b/Documentations/COMPLETE_GAME_WORKFLOW.md
index 12beb10b..eac61973 100644
--- a/Documentations/COMPLETE_GAME_WORKFLOW.md
+++ b/Documentations/COMPLETE_GAME_WORKFLOW.md
@@ -970,6 +970,8 @@ socket.on('game:ended', {
   message: string;
   finalPositions: PlayerPosition[];
   timestamp: string;
+  reason?: string;               // Optional: 'gamemaster_left' if GM disconnected
+  gamemasterName?: string;       // Optional: GM name if GM left
 });
 
 // Server → All Players: Cleanup complete
@@ -980,6 +982,36 @@ socket.on('game:cleanup-complete', {
 });
 ```
 
+**Game End Scenarios**:
+
+1. **Normal Win** (Player reaches position 100):
+   ```typescript
+   {
+     winner: "player-uuid",
+     winnerName: "Alice",
+     message: "🎉 Alice won the game! Congratulations!",
+     finalPositions: [...],
+     timestamp: "2025-11-06T..."
+   }
+   ```
+
+2. **Gamemaster Disconnect** (Game cancelled):
+   ```typescript
+   {
+     reason: "gamemaster_left",
+     gamemasterName: "Bob",
+     message: "🎭 Gamemaster Bob left. Game has ended.",
+     timestamp: "2025-11-06T..."
+   }
+   ```
+   
+   **Behavior**:
+   - Game immediately cancelled when gamemaster disconnects
+   - All players notified via `game:ended` event
+   - Database updated: `state = CANCELLED`, `enddate = now`
+   - All Redis data and socket connections cleaned up
+   - No winner recorded (game didn't complete normally)
+
 ---
 
 #### Error Events
diff --git a/Documentations/COMPLETE_GAME_WORKFLOW.pdf b/Documentations/COMPLETE_GAME_WORKFLOW.pdf
index 7a10fb58..08e14ee5 100644
Binary files a/Documentations/COMPLETE_GAME_WORKFLOW.pdf and b/Documentations/COMPLETE_GAME_WORKFLOW.pdf differ
diff --git a/SerpentRace_Backend/src/Application/Services/GameWebSocketService.ts b/SerpentRace_Backend/src/Application/Services/GameWebSocketService.ts
index 1a44e9c2..297f3cc9 100644
--- a/SerpentRace_Backend/src/Application/Services/GameWebSocketService.ts
+++ b/SerpentRace_Backend/src/Application/Services/GameWebSocketService.ts
@@ -1139,6 +1139,36 @@ export class GameWebSocketService {
         // If the socket was in a game, handle cleanup
         if (socket.gameCode && socket.playerName) {
             try {
+                // Check if this player is the gamemaster
+                const game = await this.gameRepository.findByGameCode(socket.gameCode);
+                const isGamemaster = game && socket.userId && game.createdby === socket.userId;
+
+                // If gamemaster leaves, end the game immediately
+                if (isGamemaster && game) {
+                    logOther(`Gamemaster ${socket.playerName} left game ${socket.gameCode}, ending game`);
+                    
+                    const gameRoomName = `game_${socket.gameCode}`;
+                    
+                    // Notify all players
+                    this.io.of('/game').to(gameRoomName).emit('game:ended', {
+                        reason: 'gamemaster_left',
+                        gamemasterName: socket.playerName,
+                        message: `🎭 Gamemaster ${socket.playerName} left. Game has ended.`,
+                        timestamp: new Date().toISOString()
+                    });
+
+                    // Update database
+                    await this.gameRepository.update(game.id, {
+                        state: GameState.CANCELLED,
+                        enddate: new Date()
+                    });
+
+                    // Clean up all game data
+                    await this.cleanupGameData(socket.gameCode, game.id);
+                    
+                    return; // Exit early, no need for further cleanup
+                }
+
                 // Clean up any pending card answer
                 if (socket.userId) {
                     const pendingCard = await this.getPendingCard(socket.gameCode, socket.userId);
@@ -2236,7 +2266,7 @@ export class GameWebSocketService {
             if (game) {
                 await this.gameRepository.update(game.id, {
                     state: GameState.FINISHED,
-                    winner: winnerId,
+                    winnerId: winnerId,
                     enddate: new Date()
                 });
             }