Killer.io is a fun and free multiplayer IO game. Your task is to take on the role of a guy wearing a hockey mask, next to a party at home full of innocent young people, and you happen to be holding a knife in your hand. We all know what comes next, right? So just start killing while no one is standing around, hide the body and avoid standing next to the corpses or the police will take you down. Let's play the game.