After Avengers: Secret Wars, the Marvel Cinematic Universe will enter its Mutant Saga, a direction confirmed by Marvel Studios boss Kevin Feige. Although the MCU began its interconnected storytelling in 2008, it only started introducing X-Men characters recently, mainly because 20th Century Fox held the rights until Disney acquired the studio in 2019. Now that Marvel Studios has all its toys in the sandbox, it can finally bring four of the X-Men's most intimidating villains into the MCU.
Kevin Feige confirmed the studio's big plans for the Mutant Saga in a conversation with ScreenRant, revealing that they are pondering, "how do we plan the 'mutant saga' in a very grand way?" A grand saga needs massive villains, an ambition the studio has already shown with the casting of Adam Driver as Mister Sinister. The reveal came at Disney's D23 Expo in August, where Driver crashed the X-Men panel by video to announce his character's name. "So I'm very excited to be playing the role of Maaagneto!" he teased, before correcting himself, "Even better, Nathaniel Milbury."
Comic readers know that name well. Nathan Milbury is the alias of Nathaniel Essex, better known as Mister Sinister, used while running the Nebraska orphanage where a young Scott Summers grew up, secretly experimenting on the boy the entire time.
Sinister will officially be the antagonist in Jake Schreier's X-Men reboot, which features Sadie Sink as Jean Grey, Kit Connor as Cyclops, Christopher Abbott as Professor X, Samara Weaving as Emma Frost, Inde Navarrette as Rogue, and Maya Boyd as Storm. Most of that cast was unveiled onstage at D23, with Connor and Weaving announced earlier. After the reveals, Feige promised "sagas upon sagas" of mutant stories, joking that there can be "100 more" X-Men movies. The reboot film is confirmed to arrive on May 5, 2028.
For a long time, the MCU's biggest villains have largely been Avengers villains in the comics or, in Thanos' case, a Guardians of the Galaxy one. Finally, Marvel's interconnected universe can feature a mutant as the greatest threat not only to the X-Men but to the Avengers and every other hero in its orbit. So far, Sinister is the only X-Men antagonist confirmed for the Mutant Saga, but there are at least four more who could easily join him.
X-Men Villains That Could Debut in the Mutant Saga
Apocalypse
Sinister's story is intertwined with Apocalypse, and the MCU introducing him as its first mutant movie villain could tee up the ancient one's eventual arrival. In the comics, Apocalypse is the very being who transformed Victorian-era scientist Nathaniel Essex into the ageless Mister Sinister. That connection is likely to take center stage in the MCU.
First known as En Sabah Nur, Apocalypse is believed to be the world's first mutant, hailing from ancient Egypt, which places his origin thousands of years in the past. An immortal, he has outlived entire civilizations. He endured a brutal childhood, shunned and mistreated for his odd gray skin, an upbringing that forged his infamous survival-of-the-fittest philosophy: only the strong deserve to live, and the weak should perish.
That ideology makes him a deadly foe, made worse by his habit of recruiting powerful mutants to spread it. In the comics, he has turned several X-Men into his "Horsemen," and Marvel recently cast Gen V star Asa Germann as Warren Worthington III, also known as Angel, one of the X-Men who most famously suffered that fate. That arc is a huge part of Angel's story, so casting him in the first mutant film is another significant sign of Apocalypse's shadow over the Mutant Saga.
Magneto
It's highly improbable that Marvel tells X-Men stories without Magneto. He's one of the most iconic villains ever written and, at the same time, an ally to the team when it suits him. Professor Charles Xavier, his closest friend, has been cast, which means Erik Lehnsherr exists somewhere in this universe. The character hasn't officially been cast, but he's likely to appear in the reboot. What makes Magneto so compelling is his hatred of humanity and the unsettling logic behind it.
His experience as a prisoner in Auschwitz shaped that worldview, and his philosophy has long drawn mutants to his side, hence the enduring popularity of the "Magneto was right" mantra. That sets up a potential clash between mutant factions in the MCU, much like the Fox films. This time around, though, the rest of Marvel's heroes would be caught in the crossfire, which is an even more exciting prospect.
The Brotherhood of Mutants
Magneto's mutant supremacy ideology led to the creation of the Brotherhood of Mutants, an extremist group that aids the Master of Magnetism in inciting violence against humans. The team has boasted a deep roster over the years, counting Mystique, Pyro, Sabretooth, and Quicksilver among its ranks. Even the Scarlet Witch was a member at one point. If Magneto eventually features in the Mutant Saga, his Brotherhood would likely follow.
Sentinels
The Sentinels are arguably the X-Men's greatest threat. Created by scientist Bolivar Trask, they were designed to hunt and kill mutants. For years, these killing machines have represented suffering and oppression in the history of mutantkind, making them a core part of X-Men storytelling. Many of the most iconic mutant storylines revolve around them. Days of Future Past, for example, imagined a future where Sentinels take over a ruined Earth. Then there's the popular Genosha massacre arc, in which they wiped out mutants in massive numbers, a storyline Marvel Studios' animated X-Men '97 already brought to life.
Other stories introduced even bigger synthetic threats like Master Mold, Nimrod, and Bastion, showing the program evolving beyond anyone's control. The Sentinels are set to appear in Avengers: Doomsday, as the film's trailers have shown, and they could easily carry over into the X-Men films when the universe reboots after Avengers: Secret Wars.
Geraldo Amartey is a writer at The Direct. He joined the team in 2025, bringing with him four years of experience covering entertainment news, pop culture, and fan-favorite franchises for sites like YEN, Briefly and Tuko.
