The Joker was killed by Superman before the events of the first game, but has inexplicably returned to the Injustice universe to wreak havoc once more. Whether he returned from the dead, hails from an alternate universe, or is merely a hallucination is left unanswered, but he plans to continue to plunge the world into chaos just as before.
In combat, Joker uses his revolver, knife, crowbar, joy buzzer, laughing gas canisters and a flag gun that actually fires the flag to torture his opponents. His trait allows him to get faster the more he laughs.
