The MCU’s New X-Men Villain Casting Makes Guardians Of The Galaxy 3 More Important Than Ever

Published Aug 20, 2026, 9:30 AM EDT Zoë Miskelly is an editor and second in command for Screen Rant's Movies team, having covered the entertainment industry for almost 10 years now. Zoë's love of superheroes and all things Marvel & DC started out in childhood, and has blossomed into a career getting to talk about some of the biggest and best movies and shows of all time, having previously focused on comics while working at WhatCulture. Sign in to your ScreenRant account Warning: This article contains spoilers for Spider-Man: Brand New Day.The MCU's X-Men villain casting setup means Guardians of the Galaxy Vol. 3 is all the more useful for the franchise to draw from, as the core subject matter and lore set up in this movie provides a perfect backdrop for this impending antagonist. Though the X-Men have only just started to be tied into the MCU timeline and its overarching story, the franchise has been setting up for this eventuality for quite some time. Whether by She-Hulk's references to Marvel's mutant heroes or by the unveiling of the multiverse itself, the MCU has steadily made its landscape more and more hospitable for figures like the X-Men, paving the way for the recent announcements regarding the MCU's upcoming X-Men movie and the revealed members of its cast. This has cemented one MCU X-Men villain for the film's future thus far in the form of Mister Sinister - set to be played by Adam Driver - which is notable given how a prior 2023 MCU movie connects to this character in more than one way, and has already helped set the stage for Mister Sinister to slot into the existing MCU in a natural manner that also makes him suitably imposing. Guardians Of The Galaxy 3's Story Is The Perfect Foreshadowing Of The X-Men's New MCU Villain Image via Marvel Studios Guardians of the Galaxy Vol. 3 provides one of the most extensive looks at both the extent of the genetic experimentation being done in the MCU - as the High Evolutionary seems to be on the forefront of this questionable practice - and the evil being done with it, since Rocket's backstory is wall-to-wall tragedies involving the High Evolutionary's work that are steadily unveiled over the course of its story. This works well to set the stage for Mister Sinister following the reveal that he will play a part in the MCU's X-Men movie, since the antagonist's story tends to revolve around his deeply unethical interest in genetic experimentation. Interestingly enough, Mister Sinister does have a close tie to the High Evolutionary in the comics, too, wherein the latter is inspired by the former's research, leading him down a rocky road. Though it's unlikely the MCU will replicate this exactly, mirroring this tie in the franchise could be a good way to make Mister Sinister seem like even more of a threat, and make the links between the MCU's past and future all the more clear for audiences as well. The MCU's Movie History Has Perfectly Teed Up Mister Sinister's Impending Debut Guardians of the Galaxy Vol. 3 is the MCU movie that links perhaps best to Mister Sinister's upcoming MCU story and motives thanks to its considerable focus on the kind of experiments Sinister becomes known for, but it's by no means the only MCU movie that helps set the stage for the character to appear in the movie world. For example, Spider-Man: Brand New Day plays a key role in terms of introducing Jean Grey into the MCU and introducing the devices that look set to be used later in the franchise to negate mutant characters' powers - which Spider-Man crafted in an effort to control his own mutating abilities - and that will no doubt be used by more science-focused villains like Mister Sinister in order to try to handle enemies like the X-Men. In the same vein, Deadpool & Wolverine showing that Cassandra Nova - whose reality-warping powers are shown in full force in the movie - can be dealt with via Juggernaut's psychic power neutralizing helmet underlines that someone who is able to invent things and toy with the powerset of Marvel's mutant heroes is a major threat to say the least. Hopefully, when the MCU X-Men movie releases, the film's story will capitalize on all the backdrop fully, including the major useful worldbuilding in this vein set up by Guardians of the Galaxy Vol. 3.