Assassin is a Duck role. Twice per game, they can use their special ability on someone during the meeting process to guess their role. If The Assassin is right, their target dies. If they are wrong, they die.
How to Deal with a Assassin[]
If an Assassin is confirmed to be in the game, NEVER reveal your real role, Fake claim something similar if possible, or be vague enough that the Assassin won't immediately be able to figure it out (Ex: Vigilante, Sheriff, or Avenger can all Claim "I'm goose with a kill button". Medium and Detective can say "I help find out when people are killed", Canadian And Celebrity can say "If I die the killer can get caught", etc.). If someone else claims YOUR role in an Assassin game, they are likely something similar and want to avoid being killed by the Assassin, or are evil. In either situation, don't call them out on it, or you risk being shot by the Assassin during the meeting. If you're too obvious as a dodo, the Assassin can decide to call you out on it with their shot.
Strategy:[]
When there are (Ducks + 1) amount of non-ducks in the game left, you have at least 1 usage of your ability, and there is a spy, the spy may tell you to select someone and choose a role. You should listen to them, unless they are trolling and want you to die. You can coordinate with a spy with proximity chat to help get 2 unavoidable and uncatchable kills on 2 people. If someone claims a role, they can be fake claiming, so don't guess them immediately. Ask them to confirm first, and if they can confirm themselves as that role, then you use the ability. The one exception to this is if they claim Sheriff, as they can still be Falcon or Vigilante, and in which case you can decide to call them out as a fake sheriff. If players remember you asking for confirmation of their role, and they end up killed by a Assassin later in the game, they may accuse you of being Assassin.