For those unfamiliar, a game with a traitor mechanic is just any co-op game where some subset of players’ goal is to have everyone else lose. There’s an important distinction here from hidden role games, in which players have different goals that may or may not be at odds. I thought I’d give my advice on how to design traitor mechanics.

Make a Co-op

The first step to making a game where players can betray other players is to have something they can sabotage. All players need to be working towards the same goal. This involves basically designing a co-op game. I won’t go over how to do that here (though some of my preious articles may help), but also keep in mind it doesn’t necessarily have to be a good or in-depth co-op game. For example, Saboteur is essentially a complete game without the titular saboteurs, whereas Resistance is a complete game that would involve nothing but playing success cards over and over. Secret Hitler meets a nice middle-ground, where playing without any traitors leads to a game that occasionally goes wrong but is incredibly unlikely to be lost. That leads to another important point: make it an easily winnable co-op. If the players are in danger of losing without a traitor, then the traitor players can end up feeling like they don’t need to do anything, which is boring.

Let All Players Do Everything

This is the big difference between a traitor game and an imposter game. Imposter games like Spyfall, Chameleon, or Fake Artisit in New York, are about determining which player is the imposter. You can only do that because the imposter is unable to perform as well as other players. In a traitor game, though, all players must be able to do the same actions. If a good player and a traitor are in any way not allowed to carry out the same action, then the game devolves into forcing characters into that position. In order for a traitor to blend in, you want them to do every action that a good player to do. The main decision you want the traitors to have is “do I continue helping the team in order to gain their trust, or do I sabotage them and risk blowing my cover?” This is the primary pull of the genre. If a player can’t do something nice even if they want to, you are removing choice and tension from the game.

Obfuscate

Whenever a player does something, hide it. Shuffle decks, get players to play face-down, all that jazz. Remember, make all players do it. Hide their actions whether they are good or bad, both to hide bad actions but also to sow doubt among the others. Keep things hidden until the last moment it is relevant. You can let players remove this obfuscation, but make sure it costs something. Traitors enjoy doing this as well, since it’s a way to spend resources on things other than the primary goal.

Let the Truth Come Out

There’s one other big difference between an imposter game and a traitor game, and that’s the reveal. In an imposter game, the game ends as soon as an imposter is discovered. In a traitor game, that’s not the case. If you’re making a game with traitors, don’t end the game as soon as the traitors are discovered. As I said earlier, it’s up to the traitors to decide when they are willing to risk blowing their cover. If a situation arises early in the game where blowing their cover would deal a huge blow to the team, let them do it! Design your game in such a way that if a player is discovered, they are at a huge disadvantage, but not a game-ending one. Make it cost players some resource (like time or movement) that is easy to get in the early game but hard in the late game. In Resistance, your punishment for getting found out is that you won’t be put on any missions, much worse the earlier it happens, but you’re still allowed to vote, which could throw a wrench in plans. In saboteur, you’ll likely get your tools broken and be unable to build paths, but if it’s late enough in the game you may not need to play anything. I would suggest against allowing players to be publicly and undeniably revealed (as with Battlestar Galactica’s board game), though I’ve seen it work, especially for shorter games or when it’s at a high cost to players.

Conclusion

I love traitor mechanics. They are a sure-fire way to make any co-op game more interesting (along with dealing negating the alpha player problem), but it’s not as easy as just randomly telling one player to not do the right thing. There need to be things in place to allow some players, and by extension all players, to do what they need to while avoiding or gaining suspicion.