Joker XX (usually just called Joker) is a direct descendant of the Joker, living in the 30th Century. He is the twentieth member of his family to take up the Joker identity.
His father, Joker XIX became famous for killing Batman XIX during a public ceremony. Following his father's legacy, Joker XX started a series of daring crimes and was eventually confronted by Superman XX. Joker then tried to steal from Muto, which then turned into a brief confrontation between the two criminals. However, when they realized that Superman was their common enemy, they decided to team-up and outmatched Superman on every occasion.
When Superman teamed-up with Batman XX, they were no match for both heroes and Joker XX was eventually confronted by Batman, who wanted to learn the whereabouts of Joker XIX in order to avenge his father. Unfortunately, Joker XX died when he was being confronted by Bron Wayn E7705 about the whereabouts of the last Joker, the one who killed Bron's father, the previous Batman. His death was a result of him holding a lightning attractor which--when lighting struck--attracted lightning to him and killed him. As a result of his death, Batman the 20th was unable to locate his father's killer.
- Joke Box: Joker the 20th created a compact "hyper-electronic stimulator" using his mechanical aptitude and futuristic 30th century technology.
- Mind ControlIt's capable of controlling the person it's targeted at's body. This includes involuntary movement as well as laughter.
- Joker-Ship: Capable of interstellar travel.
- This version of Joker, including all history and corresponding appearances, was erased from existence following the collapse of the original Multiverse in the 1985–86 Crisis on Infinite Earths limited series. Even though versions of the character may have since appeared, this information does not apply to those versions.
- 1 Appearances of Joker XX (Earth-One)
- 1 Images featuring Joker XX (Earth-One)
- Quotations by or about Joker XX (Earth-One)
- Character Gallery: Joker XX (Earth-One)