6. Martha Kane
First appearance: Flashpoint Vol. 2 No.1 (2011)

What makes this Joker so special? In this alternative timeline discovered by Flash in the Flashpoint storyline, the fate of Bruce Wayne has changed. During the robbery after the theater performance, it was not his parents who died, but himself.
This changed the behavior of Martha and Thomas, Bruce’s parents. Thomas became a violent Batman who does not shy away from killing, and Martha could not cope with the death of her son, so she became the new Joker.
She regularly clashes with Thomas. While he manages to save her, after Thomas rescues her, she falls back into her madness upon discovering that Bruce becomes Batman in another timeline (DC Database).