Marvel just announced its first X-Men movie. Sort of. Along with the elaborate cast announcement for Avengers: Doomsday, Marvel revealed that several stars from the original Fox X-Men series are returning, presumably as their original characters. Theres Patrick Stewart and Ian McKellen, James Marsden, Rebecca Romijn, Alan Cumming, and Kelsey Grammar, to start. The cast is still coming and well add more names when theyre revealed. But we think its safe to assume theyre playing Professor X, Magneto, Cyclops, Mystique, Nightcrawler, and Beast. This is fascinating for a bunch of reasons. The first is that there are two X-Men casts. There are the ones from the 2000 original, X-Men, and the ones from the 2011 reboot/prequel, X-Men: First Class. Of course, they came together in a subsequent film, but if you had to choose which cast was going to shift over to the MCU, you wouldve guessed the younger one. Though, to be fair, both Stewart and Grammar have already reprised their roles in Doctor Strange in the Multiverse of Madness and The Marvels. Then theres also the question of what narrative role these characters are going to play in an Avengers movie. Theyre not Avengers. Theyre X-Men. So is it possible theyre just sacrificial lambs so Doctor Doom, played by Robert Downey Jr., can prove his superiority? Would all of these actors return just to be killed off? Clearly, we dont know. We also dont know if the versions of the characters that appear in Doomsday are the same X-Men from that universe. Deadpool & Wolverine, the actual first X-Men movie in the MCU, clearly established that there are multiple versions of all of these characters. And, with the reveal that Channing Tatum is returning as Gambit, we know thats part of this. So, potentially, these are completely new ones. Or maybe theyre not even those characters.Nevertheless, its very exciting for long-time superhero film fans to see these names pop up. The Fox universe has gotten a few chances at closure in the past, but coming back for an Avengers film feels like a whole new level. Want more io9 news? Check out when to expect the latest Marvel, Star Wars, and Star Trek releases, whats next for the DC Universe on film and TV, and everything you need to know about the future of Doctor Who.