In the Earth 13 reality, Bruce murdered his parents when he was still a child and became a masked criminal when he became an adult. Bruce murdered a young woman named Barbara Gordon while she was paralyzed in a wheelchair and killed Clark Kent for exposing him to the police. When Earth 13 was being destroyed by the Monitors, Bruce followed Clark inside a portal which transported him into a parallel Earth. In the morgue, Batman and Lieutenant Gordon checked the body of the dead Clark. Batman scanned the body and found DNA samples from the murderer which matched his. Bruce confronted Batman and Nightwing at the Amusement Mile that the Joker often used as his refuge and threw explosive balls at them.
Batman attacked his doppelganger, however Bruce surprisingly overpowered him. Night Wing tried to help, however Bruce stabbed her in the belly and told her she was funnier that his Barbara who didn't put much fight when he murdered her. Batman started to get angry and used it to beat his opponent. Bruce asked Batman if there is an Arkham Asylum on this world since he said it would be better to kill him now than take him there. Batman, who swore never to kill after the murder of his parents, arranged for the Martian Manhunter to imprison him on Mars.
Similar Versions In Other Comics
In Batman: Two Faces, Bruce Wayne created a potion that would cure Harvey Dent from his alternate personality and tested the potion on himself which made him gain superhuman strength. Bruce decided to put together a costume and fight crime, however the potion created another personality in his head who liked to call himself 'The Joker'. Bruce took control of his body and killed "The Joker" personality by taking his own life.
In the alternate future of Batman: I, Joker, Joker's last descendant, Joe Collins, killed The Bruce and becomes the new grinning Batman and takes back Gotham City.
Martha Wayne from Flashpoint was the Joker as well as Tim Drake, the former Robin and Bruce's second foster son, in the Batman Beyond Universe.
In The Dark Knight Strikes Again, which takes place in the alternate world of Earth-31,Batman fired Dick Grayson for his gross incompetence which made Dick went through an experimental procedure that made him nigh immortal through cellular regeneration, and he was actually driven insane. Dick became the second Joker and killed several superheroes who were retired. Batman threw him into the lava in the end, killing him.
In Death of The Family in the New 52's crossover event with Batman related titles, Joker abducted Damian Wayne and presented him a Joker toxin and told Damian to kill his own father or Batman will kill him. Damian then committed suicide and Joker killed Batman, who turned out to be a fake in the end.
- He was inspired by Owl-Man.