The Joker

The Joker is a supervillain that operates in Gotham City, who serves as the arch-nemesis of Batman. Often dressed in suits or clown-like attire, the Joker is a psychopathic, mass murdering serial killer known for leaving smiles on the faces of his victims. The Joker is responsible for a number of tragedies in the lives of Batman and his allies, such as the murder of Jason Todd.

First encounter with the Dark Knight
The Joker's first encounter with Batman took place in the early days of Batman's war on crime, when the Joker threatened to poison Gotham City's water supply.

Legacy
Following the demise of the Joker, Dick Grayson took on the "Joker" moniker as he began murdering costumed heroes.

Appearances

 * Batman: Year One
 * Batman #407 (Mentioned)
 * All Star Batman and Robin: The Boy Wonder
 * All Star Batman and Robin: The Boy Wonder #8
 * The Dark Knight Returns: The Last Crusade
 * Batman: The Dark Knight Returns
 * The Dark Knight Returns
 * Dark Knight Triumphant
 * Hunt the Dark Knight
 * The Dark Knight Falls (Corpse only)

Animated films

 * Batman: Year One (Mentioned)
 * Batman: The Dark Knight Returns - Part 1
 * Batman: The Dark Knight Returns - Part 2