Jack Napier, a.k.a. the Joker. After years of madness, he's finally sane. But there's something wrong. Something's not right. According to his psychiatrist, there's no Bat. Nobody in Gotham City has heard of a superhero named Batman. The Justice League doesn't have a guy who dresses like a bat.

And that's wrong. That can't be. Because if there's one thing that Jack knows, it's that there can't be a Joker without a Batman.

Originally a response to a thread on r/WritingPrompts by /u/Aladayle. Also available on Archive of Our Own (AO3), SpaceBattles (SB), and /r/Acylion (Reddit).