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The addition of Dante Pereira-Olson to Joaquin Phoenix’s Joker movie as a young Bruce Wayne both connects the project more concretely to DC Entertainment’s Batman mythos and underscores a basic truth, commonly misunderstood, about Bruce Wayne as a character.

That Joker is one of three Batman prequel projects currently in the works or on air in some form or another — Pennyworth, centering on a young version of Batman’s trusted butler, is in development, and Gotham, the series following the pre-Batman exploits of Commissioner Gordon, will debut its fifth season on Fox in 2019 — speaks to the belief that there is something inherently interesting in the backstory of almost everyone attached to the Dark Knight, even before Bruce gets the idea of emulating the leathery wings of tiny mammals as a disguise.

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