Joker movie 2: Director Todd Phillips' crossover comments could mean an epic sequel

“Part of the movie is a search for identity. Arthur’s idea is to fit in and belong somewhere,” Phillips said.

“So this idea of Arthur not knowing who his father is, where he came from, if he was adopted, what the story was, was another element in his search for identity.”

Though his remarks are, in themselves, somewhat ambiguous, Phillips leaving the possibility of the Joker and Batman being brothers open points to an increased chance of a second movie.

With such a rich background to be explored — and plenty of potential routes to take with the plot — fans would be devastated if opportunity for the relationship to be delved further into were passed up.