The Flash movie should pay-off Christopher Nolan's second Batman tease from the end of The Dark Knight RisesBen Affleck and Michael Keaton will both be reprising the role of Batman in The Flash, and paying off Nolan's Batman cliffhanger would connect his trilogy to the DCEU as well. Beginning with 2013's Man of Steel, the DC Extended Universe currently consists of eight superhero films, all sharing continuity with one another but (ostensibly) separate from recent portrayals of the same characters, including Nolan's The Dark Knight Trilogy and Superman Returns, as well as from CW's Arrowverse.

A brief pseudo-dream sequence in Batman v Superman: Dawn of Justice already hinted at the Flash's time- and reality-warping abilities, and early descriptions of the hero's standalone film suggest it will expand upon these powers, drawing on the alternate reality angle of the comics' Flashpoint event. If the outcome of the storyline remains the same, this is expected to be DCEU's first big step in establishing a multiverse, matching the moves made by the MCU in Avengers: EndgameWandaVision, and Doctor Strange in the Multiverse of Madness.

Related: The Flash: DCEU Multiverse Is Copying The Arrowverse Model

After playing the new but suggestively-named character Robin John Blake in The Dark Knight Rises, Joseph Gordon-Levitt is primed to return as another alternate-universe Batman in The Flash. The presence of alternate versions of the same character has already been confirmed, as Michael Keaton will, after an absence of 30 years, once again be playing Bruce Wayne, joining Affleck, the DCEU's incumbent Batman. Keaton's two appearances in Tim Burton's Batman films are closely linked to the one-off portrayals by Val Kilmer and George Clooney, so the Christopher Nolan trilogy is the only other major live-action Batman saga in recent memory that is not yet represented.

Batman running down a hall with bats flying behind him in Batman Begins.

A return by Christian Bale is unlikely, but Bruce Wayne's retirement at the end of Nolan's trilogy actually plays into that very well, as it was hinted that Joseph Gordon-Levitt's character, in finding the Batcave, would inherit the mantle of Batman. There is a precedent for this baton-passing in the comics, but Gordon-Levitt could alternately become a version of Robin, as teased by his character's first name. Given the apparent death of at least one Robin in the DCEU, as evinced by the Joker-graffitied suit in Batman v Superman, this would certainly inspire a strong reaction from Affleck's Batman.

The establishment of a retroactive multiverse is a bold step for the DCEU and the casting of Michael Keaton, an Oscar nominee and one of the most iconic Batman actors, announced it in style. A link to Christopher Nolan's The Dark Knight Trilogy, one of the most critically acclaimed superhero sagas ever, would add additional gravitas to the concept, potentially on par with the addition of Joaquin Phoenix's Joker to Jared Leto's. The opportunity to pay off a longstanding cliffhanger only makes the prospect more enticing.

Next: Every Actor Who's Played Batman In Live-Action

Key Release Dates