Joker

The Joker is the main antagonist of Christopher Nolan's film The Dark Knight (2008), based on the DC Comics supervillain of the same name. The role was played by Australian actor Heath Ledger.
Character description:
The Joker first appears at the beginning of the film as part of a gang of six people in clown masks. They are robbing a bank owned by the mafia. He tricks four of them into killing each other, and then kills the last one himself and runs away with the money. 
Joker's philosophy: He is a moral philosopher, provocateur and empiricist. He is motivated to prove that the liquidation of the state will lead to the creation of a freer and more just society. 
Appearance: The Joker wears a traditional costume with a purple-green color palette, and his disfigured clown appearance is the result of blurred makeup covering the facial scars of Glasgow's smile.