Ben Affleck will reprise his role as Batman in Batman v Superman: Dawn of Justice, saw Cavill’s Superman going against a new Batman, now played by Ben Affleck, but it wasn’t the big success Warner Bros. was expecting.
Still, the confirmed to return in The Flash, which explains how Pattinson’s version can be part of this universe, too.
The Flash will bring the multiverse to the big screen, a concept that had already been established in the TV side of the DCEU through the "Crisis on Infinite Earths" storyline, where Tim Burton’s 1989 Batman film, and Ben Affleck’s. Speaking to Vanity Fair, The Flash director Andy Muschietti explained that the film is “a bit of a hinge in the sense that it presents a story that implies a unified universe where all cinematic iterations that we’ve seen before are valid”, adding that it’s inclusive in the sense that “all that you’ve seen exists, and everything that you will see exists” as it’s all part of the same universe. This explains how Robert Pattinson’s Batman and Ben Affleck’s can exist in the DCEU, as they’re from different branches of the same universe.
According to Muschietti, the addition of The Batman, so he could make an appearance in The Flash, set to be released a year later. Or, simply, The Flash could include a reference to Pattinson’s Batman, perhaps as an Easter egg for fans to look for.
The multiverse and what The Flash will do with it and the different Batmen makes it easy for Keaton and Affleck to return and not mess with what Reeves is doing with the character. Pattinson’s version doesn’t have to fit the DCEU’s continuity and Affleck’s won’t have to change for Pattinson’s to make sense, allowing the studio to explore different versions of some of DC Comics’ most popular characters. However, Ben Affleck’s future in the DCEU after The Flash is unknown, and this could be his final appearance as Batman.
