I think its safe to say that director Christopher Nolan had some idea for a future for The Joker in The Dark Knight Rises, but the tragic death of Heath Ledger derailed any possibility for a future appearance of The Joker. Naturally though, the trivia buffs among us wondered what role, if any, The Joker might have had in TDKR.
Greg Cox has posited a semi-official answer. Cox, a well-known author of several licensed sci-fi and comic-related novels, penned the official novelization of The Dark Knight Rises. The book was released this week, and courtesy of Nuke the Fridge, we have the passage that suggests what become of The Joker between The Dark Knight through the events of Rises.
Now that the Dent Act had made it all but impossible for the city’s criminals to cop an insanity plea, [Blackgate Prison] had replaced Arkham Asylum as a preferred location for imprisoning both convicted and suspected felons. The worst of the worst were sent here, except for the Joker, who, rumor had it, was locked away as Arkham’s sole remaining inmate. Or perhaps he had escaped. Nobody was really sure. Not even Selina.
Makes sense. Joker’s machinations led to the death of Harvey Dent no matter which version you believe, so to suggest that he’d get “special treatment” as a prisoner should not be so unbelievable.
In addition, one inspired artist on Reddit (via Movie Moron) storyboarded a sequence to show The Joker’s fate. It almost could have been done as homage to Ledger without him, not that I think anyone would have had the heart to do.
For me, when I saw the scene in The Dark Knight Rises with Jonathan Crane (Cillian Murphy) presiding over the sentencing (“Exile or death!”) of Gotham’s powerful and elite, I immediately wondered if that was the role Nolan had in mind for Ledger’s Joker. I guess we’ll never know.