Who is the Joker?

A Psychopathic Criminal: The Joker. The villain terrorizes Gotham City and makes Batman forget about vacations. He may not have super powers, but he does have an ingenious super brain! He uses his expertise in chemistry to build dangerous weapons. He also lives up to his looks and many of his crimes are set up like magic tricks by a clown. Whether it's razor-sharp playing cards or deadly bouquets of flowers, the Joker never runs out of ideas. The only one who can stop him and his chaos is Batman. The Protector and Joker face off in a decades-long battle for Gotham City.