The Joker is a fictional character that appears in comic books published by DC Comics. The archenemy of the superhero Batman, the Joker is a master criminal whose characterization has varied from a violent and murderous sociopath, causing chaos and committing crimes for his own amusement, to a goofy and virtually harmless trickster-thief. The Joker's real identity is unknown, and there have been different takes on his origin.