Social Deduction Game

You're a sneaky little impostor
Aren't you? Aren't you?

A social deduction game's premise is simple: there are at least two teams with contrary goals. One of these teams is often smaller, villainous, hidden within the larger group, and working together to achieve some nefarious goal such as sabotage or killing the other players. The other players then have to figure out who the traitors are. This is often done through some Witch Hunt-esque combination of questioning, catching them in the act, or voting them off, while the traitors avoid suspicion by deflecting, bluffing, or pretending to be innocent.

The parlor game Werewolf (1997) is the Trope Codifier and many games follow this template: there's a secret killer hidden within the group, and the rest have to figure out who it is before all Ten Little Murder Victims are offed one by one. However, there are many ways to expand and complicate the Social Deduction Game, such as by adding more teams, roles, and various other mechanics, or by mixing it with other genres. Some games have this as an optional or random aspect of the larger gameplay.

Compare The Mole, as identifying the hidden traitor/s is usually one of the objectives of the game, Ten Little Murder Victims, and Blending-In Stealth Gameplay, which usually involves hiding from the AI. On the Sliding Scale of Cooperation vs. Competition, this genre falls under either "Treacherous Teammate" (when there is only one traitor player) or "Informed Minority vs. Uninformed Majority" (when there are more traitors and they cooperate with each other). Insane Troll Logic and Right for the Wrong Reasons are frequent in these types of games.

See also Asymmetric Multiplayer, Variable Player Goals and Player Elimination.

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Examples:

Anime & Manga

• Cipher Academy features the "Murder at Cipher Academy" game, which is part of the process to select the Class Leading Private. Players are immersed in a murder mystery scenario, and, similarly to "Werewolf", each of them has a secret role, including a killer who must evade identification. This being the Cipher Academy, the game is combined with puzzles that reveal hints to the killer's identity. Players must unravel these puzzles while interrogating one another to uncover the truth. To make matters more complicated, each player has a hidden agenda and a different victory condition. Players also have special skills, such as being able to refuse answering when interrogated, or being able to instantly solve specific puzzles.
• The Future Arc in Danganronpa 3: The End of Hope's Peak High School has the Future Foundation members forced to play an In-Universe killing game where each member wears a wrist band with a 'forbidden action' that will trigger a lethal injection if the victim does it. The band also forces everyone to sleep at specific intervals while an attacker is given enough time to kill one person, so the players must either root out the traitor or die. It's subverted since there is no attacker, one person is always left awake every interval and forced to kill themselves by watching a brainwashing video.

Live-Action TV

• The Mole is a spy-themed reality-tv show where the contestants work together to complete various tasks to earn a cash prize that only one of them will win. One of the contestants, however, is The Mole, a double agent hired by the producers themselves to sabotage the group's missions and keep money from the pot. At the end of each episode, the contestants take a quiz on The Mole's identity, with the player having the lowest score being "Executed" and removed from the game. The winner is the player who figures out The Mole's identity, surviving until the very end and has the highest score on the final quiz given.
• Only Murders in the Building: "The Tell" is themed around "Son of Sam", a parlor game of Oliver's. It is a social deduction game themed similar to Werewolf (1997) (but themed around David Berkowitz, the Son of Sam killer). Characters are handed cards — most are "innocent blondes", but one is the Son of Sam killer, who pinches/"kills" an unknowing victim in each round. The group must then vote on who they think the killer is (if Oliver doesn't get it before them) lest the killer gets them all; if an accused person turns out to be innocent, they die as well. Oliver prides himself on always guessing right.
• Taskmaster does this occasionally on team tasks, where one team member is given a different goal from the rest of the team.
  • In episode 4 of series 12, Morgana Robinson earned two bonus points by getting her teammates to say "submarine" (without letting her teammates know she was trying to get them to say "submarine", and without saying "submarine" herself).
  • In episode 3 of series 14, John Kearns had the secret task of sabotaging his team. He earned points only if his team lost the team task, and no one on his team accused him of sabotaging them.
• Trapped! is a British kids TV game show in which, every round, the contestants are set a task, but a player is secretly nominated to be a saboteur who must try and stop them from finishing the task without the others realising what they're doing. If the players complete the task, the saboteur is removed from the game, but if the players fail, they vote on who they think the saboteur was and the player with the most votes is eliminated instead.
• Who Wants to Be a Superhero?
  • Ostensibly, people who'd created their own superhero identities were chosen as contestants for the show, including one bearded man named "Rotriart." After the group all met each other for a cocktail hour and headed for the manor where they'd be staying, this hero revealed that "Rotiart spelled backwards is 'TRAITOR!'", and that he'd been planted as The Mole to trick the group into exposing some less-than-ideal secrets, which in turn led to the first elimination before the game had technically begun. Needless to say, the other contestants immediately realized that they were in for a tougher challenge than expected.
  • Other episodes of the show used similar tricks, with hired actors pretending to be various groups of people—such as some friendly waitstaff who asked questions about the heroes' secret identities or a bunch of adoring fans who tried to distract the contestants with requests for photos and autographs during a mission in an amusement park. It got to the point where any kind of social group had to be treated with suspicion.

Other

• "Wink Murder" is a party game where one guest is secretly cast as a serial killer who 'kills' the others by winking at them. The rest of the guests must deduce who the killer is before they get winked at.

Roleplay

• The Murderverse is a Shared Universe of games that mostly combine Mafia-type gameplay with character-based roleplaying, though there are a few games that break from the formula slightly.^note Murder U, for example, runs on Danganronpa rules where anyone may kill at any time, while in Monster Smash, the bloodthirsty monsters aren't an informed minority.

Tabletop Games

• The licensed board game based on Battlestar Galactica (2003) varies the formula by having players draw a second set of loyalties halfway through the game, with the effect that a previously "human" player can be activated as a cylon Sleeper Agent.
• The card game Bang! features randomly assigned hidden roles, and corresponding Variable Player Goals. A big part of the game is figuring out who is on which side, and whose goals align (at least temporarily) with your own.
• Blood on the Clocktower sees each player secretly assigned a character with a unique ability off of a pre-defined script, with character types split into Townsfolk (good players with beneficial abilities), Outsiders (good players with detrimental abilities), Minions (evil players who mess with the good team) and the Demon (an evil player who is (usually) the one responsible for killing players at night). The good team wins if they kill the demon (usually via execution), and the evil team wins if only two players survive (one of which is the Demon).
• Burke's Gambit: Players take on the role of the crew of a spaceship, are secretly split into 2 teams - regular crew members and Acquisition Support Specialists - and one player is also secretly infected with an alien parasite. The specialists want the infected player to survive the journey back to earth, while the crew are trying to figure out which player is infected and get them Thrown Out the Airlock.
• Dead of Winter is a Zombie Apocalypse survival horror board game, where players work together to gather supplies, resolve crises and protect their colony from zombies. However each player also has a special victory condition, unique to them, and some of these can only trigger if the colony collapses, requiring players with them to sabotage the colony without the other players realising they're a traitor.
• Deception Murder In Hong Kong has a variant of the Werewolf premise: players can be a Murderer, an Accomplice, a Forensic Scientist, a Witness, or an Investigator. The Forensic Scientist knows who the Murderer is and must leave 'evidence' pointing the rest of the players to the Murderer, who can evade or mislead with the help of the Accomplice.
• Inhuman Conditions has two players, where the investigator needs to determine if the suspect is either a human (who acts normally) or a robot (which has to abide by certain quirks during interrogation). The investigator wins by correctly identifying the role, and the suspect wins by being identified as a human - if the suspect is a human, both players win or lose together, while a robot makes it adversarial.
• Task Force Games's Intruder, which was based on the film Alien. Nexus magazine #7 has an article called "Space Zombies" which presents a two-player variant for Intruder. Before the game starts, the Intruder takes over the minds of two of the human crewmen (called "Zombies") and the Intruder player can take control of them from the human player during the game. If the human player can discover which of his crewmen are Zombies, he can kill them. If a Zombie Engineer constructs a weapon, it will automatically malfunction, revealing to the human player that the Engineer is a Zombie. If the human player tries to have a Zombie attack the Intruder, the Intruder player tells him that the crewman won't do it.
• One Night Ultimate Werewolf simplifies the formula. The entire game takes place over one night as the title suggests with the various roles performing actions during the night or having special abilities during the day. During the day phase, the players debate who among them is a werewolf. The day phase ends with the players voting on who they think is the werewolf and the one with the most votes is eliminated. The Villager team wins if a werewolf is killed, the Werewolf team wins if they both survive, and the Tanner wins if he himself is killed.
• The Resistance and its Arthurian version Avalon. There are spies (informed minority) within a greater group of government agents (uninformed majority); the latter only knows how many spies there are and not who is one. Players go on 'missions' that must be approved by the group; during the mission, 'good' members turn in Mission Success cards while spies can sabotage the mission by turning in a Mission Fail card (at the risk of their identity being exposed). The game continues in this manner until one team gets three points.
• The card game Saboteur (and its Saboteur 2 expansion) features randomly assigned hidden roles, and corresponding Variable Player Goals. A big part of the game is figuring out who is on which side, and whose goals align with your own.
• Secret Hitler: Among the players, most are Liberals, some are secretly Fascists, and one Fascist is Hitler. The Fascists know who each other are (except that Hitler doesn't know who the others are), and must covertly pass fascist policies (done through a "President" and an elected "Chancellor" who choose from randomly-drawn liberal/fascist cards) without the liberals suspecting who they are. The liberals win if five of their policies are enacted; fascists win with six, but they can also win if Hitler is elected Chancellor past a certain point.
• Shadows over Camelot is primarily a cooperative game, but there's a chance (proportionate to the number of players) that one player is a traitor trying to destroy Camelot. The loyal knights don't need to expose the traitor to win, but their final score is reduced by two points if they fail to, which can mean a last-minute defeat.
• Werewolf (1997) and its predecessor Mafia are the Trope Codifier. Players are assigned various 'villager' or 'civilian' roles (some of whom have special abilities), and there's at least one werewolf or mafioso; each round, the werewolves off one villager during the night. During the day, the rest have to figure out who the werewolves are, and can choose to execute someone they suspect is a werewolf (although the werewolves can misdirect them as well). The villagers win if they execute all the werewolves, while the werewolves win if they off enough villagers that they can block any further werewolf executions (making killing the rest of the villagers a Foregone Conclusion).
• The Werewolves of Miller's Hollow is a more complex version of Werewolf (1997), with more roles and cards. The premise is still a Social Deduction Game, however, as villagers have to root out the werewolves who are killing them by voting on who they think they are.
• Two Rooms And A Boom Is a variant where the two teams are of equal size. Players are divided into two teams and are distributed into two rooms. One team has a bomber and the other has a president. During each round, some players will switch rooms. The team with the bomber wins if the bomber and president are in the same room at the end of the game, and the other team wins if they are not. If there is a odd number of players, then one player is the gambler, whose goal is to predict which team will win.
• Wordwolf is a game where each player is assigned a word, but one player (the werewolf) is assigned a different word from the others that is related to the others' word. After a few minutes of discussion the players will vote on who they think is the werewolf; if they correctly pick the werewolf the werewolf still has a chance to win through making a guess on the others' word. The game was originally outlined as a simple word game on the creator's blog, but has since had published tabletop and video game adaptations.

Video Games

• Among Us features a bunch of Ambiguously Human creatures scurrying around a spaceship/research station/space station, with at least one "Impostor" among them. The Crewmates run around the maps and do maintenance tasks, while the Impostor blends among them and tries to sabotage the facility and kill them all without anyone noticing or suspecting them during team meetings. The Impostor(s) win if Crewmates no longer outnumber them, making victory a mathematical certainty, or if the Crewmates fail to repair a sabotage in time. The Crewmates win if they finish all their tasks (something ghosts of dead Crewmates can still help with) or vote out all the Impostors. Impostors have access to features that let them kill more effectively, such as using air vents to relocate instantly across the map, but of course being caught diving in or popping out of a vent by a Crewmate is a death sentence, as is getting caught faking certain tasks that have specific progress animations.
• Barotrauma is about a crew trying to survive in a submarine at the bottom of the ocean. The game has a 'traitor' mechanic that can be enabled; traitors are given secret objectives, which usually involve sabotaging the submarine, murdering another crewmember, or setting up monster threats by cultivating mudraptor eggs or spreading The Virus.
• Deceit's hidden faction is the Infected, who have The Virus and whose goal is to convert or kill the other players, who must survive in this desolate area by picking up supplies. At night the Infected can turn into monsters and pick off the others. Innocent players can deal with suspected Infected by shooting them during the day, but they must still convince the rest of the players during the succeeding vote.
• Goose Goose Duck: A group of ducks must determine who among them are murderous ducks or other dangerous birds before they are taken out in one form or another. Along with the Geese and Ducks, there are the Falcon, who strives to be the last bird standing, the Dodo, who wins by being voted out of the game, and the Vulture, who wins by devouring the bodies of the dead.
• The Jackbox Party Pack:
  • In "Fakin' It" from Party Pack 3, each round the players are given a task to do (such as hold up a number of fingers, make a funny face, etc.). One player, the Faker, doesn't know what the task is and has to blend in as long as possible without getting found out.
  • "Push the Button" from Party Pack 6 is a sci-fi themed game set on a space shuttle. Players have a set amount of time to deduce who among them are aliens in disguise through a series of tests. Aliens are given different prompts during these tests (which diverge more and more from the human prompts as the game progresses), so they must attempt to blend in with the humans. Aliens also have access to two "hacks" per game, which they can use on humans so they will get the alien prompts or themselves to get the human prompt. The humans win if they successfully guess which players are aliens and jettison them, while the aliens win if the humans run out of time or vote attempts, or they trick the humans into throwing one of their own out the airlock.
  • "Hypnotorius" from Party Pack 10 is a game where players are given a secret role from one of two or three categories and must answer questions in-character. They then have to figure out who among them is in a similar category as them, and which of the players is an "Outlier" who is the only one in their category.
• Lost Dimension tasks the protagonist with ascending a pillar while determining which member of his group is the traitor on each floor. Notably, the traitors are randomly chosen each time a new game is made, except for the very first one in the first playthrough, who is always George Jackman.
• The Secret Neighbor Spin-Off of Hello Neighbor has players control one of a group of children attempting to rescue their friend from the basement. However, one of them is actually the Neighbor in disguise trying to pick off the children one by one before they can figure out which one is taking them out.
• Deceive Inc. is a First-Person Shooter where all players are spies trying to steal the same MacGuffin. Each player starts the round disguised as an NPC, and can take on the appearance of any NPC they encounter. Identifying enemy spies among the crowds of NPCs wandering each mission is a core mechanic of the game.
• RuneScape has minigame called Heist where players are divided into Guards and Bandits. Bandits have the ability to disguise themselves as NPCs and must steal loot without being caught. Guards get punished if they falsely accuse too many NPCs of being bandits.
• In Space Station 13, the different crewmembers must do their jobs and survive until they are evacuated. Each round gives you "Antagonists" which have an objective, usually related to sabotage, murder, and destruction. In most modes, they spawn directly from normal crewmen and it's the job of the security department and the rest of the crew to discover them. The hidden antagonist roles include "Traitors", which are normal crewman who secretly worked for The Syndicate and have access to secret and deadly tools, "Changelings", shape-shifting aliens who can absorb other people's identities, "Cultists", followers of a Religion of Evil trying to summon Nar'Sie by forcefully converting crewmembers, and "Revolutionaries", low-ranking employees who try to recruit from non-revolutionary crewmembers in order to overthrow the Captain and Heads of Department.
• SpyParty is a one-versus-one social deduction game. The core concept is Blending-In Stealth Gameplay: the Spy must try to mingle with the other NPC guests while the Sniper watches the party with an incredibly obvious Laser Sight. The Spy must either complete all missions or trick the Sniper into shooting an innocent victim. The Sniper must either kill the Spy or spook the Spy into not completing their tasks. The challenge lies in how well players can blend in among the NPC crowd (as the Spy) or how well they can detect the other player's 'tells' (as the Sniper).
• Halfbrick Studios internally tested, but ultimately squashed a hybrid of social deduction and Turn-Based Strategy codenamed Tank Tactics. The premise is that each player pilots a tank across a grid, then can move and fire at each other based on action points, the last person standing wins; the twist comes in how action points could be passed voluntarily between one other, and eliminated players formed a jury that could vote to also award points to active players. Notably, the prototype was scrapped for being too addictive — players in the Halfbrick office were eager to join in the game and developed a meta strategy of daisy-chaining all their points into a single player who would have the power to take out who they agreed to eliminate or not, resulting in an intense honor-based network of interpersonal discussion and heightened sensitivity to trust and betrayal. The game ultimately had to be stopped due to having a sizeable effect on studio morale and productivity, with an increasing consensus that the negotiation aspects started to get too personal.
• Throne of Lies mixes the social deduction game with medieval politics. There are three factions; the 'good' one is the Blue Dragons, who aim to keep the peace in the kingdom and must root out the Unseen criminals and the Cult of Mithras. There are various roles, and the 'sniff out the traitors' aspect is complicated with how the roles' allegiances can change at any time.
• Tom and Jerry Chase has the "Aliens!" mini-game, where the objective is to expose and dispatch all the aliens or, if you are on the alien team, knock out all the opponents before they expose you.
• Town of Salem has three factions: the Townies (who must survive to the end of the game but don't know who the other townies are), the Mafia (who want to kill everyone and do know who their teammates are), and the neutral parties (who have their own individual win conditions). Townies and Mafias can only win if the other party all dies. Each day, the townspeople vote on who to lynch. A later update added the Coven as an additional faction opposed to both the Town and the Mafia, who eventually replaced the Mafia entirely as the sequel's main antagonists.
• Trouble in Terrorist Town, one of the built-in game modes for Garry's Mod, features a terrorist faction in which some members have turned on the cause and aim to kill everyone else. Traitors know who their teammates are, but the terrorist cell at large does not. Meanwhile, innocent players must piece together who the traitors are from corpses left behind and their interactions with other players, with the Detective role — designed to help weed out traitors — randomly assigned to one player for every eight players on the server.
• Unfortunate Spacemen combines this with First-Person Shooter and a touch of Survival Horror with its main Shapeshifter game mode. One player is the Monster who is disguised as a human and is trying to eliminate the Spacemen. The Spacemen need to complete tasks in order to call a rescue shuttle to escape, while being on the lookout for suspicious activity so that they could vote off the imposter at set intervals of time; they could also try to kill the Monster if they find it, but as the Monster is significantly stronger than any one Spaceman, ganging up on it with heavier weapons is pretty much necessary. There is also a Traitor available that is biologically a human but works against the Spacemen in their own way, like sabotaging equipment.
• Untrusted - Web of Cybercrime has three factions: NETSEC (a group of hackers, who in order to win, must either complete a hacking task in a hacking minigame, or eliminate all agents — they have numbers, but do not know each other), the AGENTS (who can win by tricking the hackers into giving them control, or by arresting/killing all NETSEC), and the neutral classes (who have their own individual win conditions and can very often side with either). The game includes a hacking minigame, where hacking actions are performed during days and actions toward other players similar to other games (occupations, etc.) are performed during the night.
• In Werewolves Online, the villagers must figure out which members of their group are the Werewolves, who win if they kill them all.
• The Doom mod WhoDunIt. One of the players is the Murderer, armed with a variety of weapons and gadgets, and his goal is to kill everyone else. All the other players are Innocents, trying to identify and take out the killer. If an Innocent kills the wrong person, he's marked with a Yellow Aura (1st kill) or a Red Aura (2nd kill), which gives other players free rein to harm or kill them respectively (this is mostly a measure against griefers).

Visual Novels

• Danganronpa is a single-player example. The games are divided into chapters, and in each chapter, one of the students will commit murder, forcing the rest of the characters to investigate and then take part in a Class Trial: If they get the murderer right, the murderer is executed, if they get them wrong, everyone but the murderer is killed off.
• Gnosia is essentially Werewolf (1997) in space. The Gnosia are infected humans who will kill everyone on the space ship if they are not discovered and confined to cold sleep. Unfortunately for the crew, sometimes there will be a human who worships the Gnosia and is willing to lie for their sakes, and it is also discovered that sometimes a human is a "Bug" who will destroy the universe if they are not confined by the time either the crew or Gnosia claim victory.
• In High School Story Book 3 Chapter 15, a premium scene allows Jordan and their friends to have an afterparty for the prom where they play "Mafia." Maria is the mafia.
• Raging Loop is about a village that must deduce who among them are werewolves and execute them before they are all killed. Notably, each of its three routes have you play different roles, with the first route being a normal villager (though the main character notably isn't active in this due to outside circumstances, you still see the entire thing unfold), the Snake (which functions as the Seer), and lastly as a wolf.
• Your Turn to Die has one form the Main Game of each chapter. Each round, the protagonists have to choose one of their own and vote them off. If they vote off the Keymaster, everybody dies immediately; the Sacrifice is executed unless they get the most votes, in which case they and a person of their choice are allowed to escape and everybody else dies; the Sage knows who the Keymaster is; the Commoners are ordinary.

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