Born from the nightmares of the Dark Multiverse, the Batman Who Laughs is a hybrid version of the Batman and The Joker from Earth-22. This twisted version of Batman was created when nano toxins from The Jokers heart were released into Bruce Waynes bloodstream, causing the Dark Knights perfect mind to merge with the warped psyche of the Clown Prince of Crime. He soon became part of an attempt to plunge the entire Multiverse into ultra violence, chaos, and utter darkness. After being initially defeated, the Batman Who Laughs managed to survive and remains a threat to the greatest heroes of the Multiverse.