Despite the claims that people are done with the Marvel Cinematic Universe, fans tuned in for a five-hour news stream of chairs being brought out that confirmed the cast of Avengers: Doomsday. Many MCU teams were present, including The Fantastic Four and Thunderbolts, along with heroes like Captain America, Shang-Chi, Black Panther, Ant-Man, and Thor, to name a few. Yet, the biggest shock was the inclusion of so many X-Men characters.
There have been X-Men teases throughout the MCU’s Multiverse Saga, notably Patrick Stewart’s cameo in Doctor Strange in the Multiverse of Madness, Kelsey Grammer as Beast at the end of The Marvels, and of course, various X-Men characters like Deadpool, Wolverine, Gambit, and X-23 in Deadpool & Wolverine. Yet Avengers: Doomsday not only confirmed that Stewart and Grammer were returning, but so would Ian McKellen as Magneto, Alan Cumming as Nightcrawler, Channing Tatum as Gambit, Rebecca Romijn as Mystique, and James Marsden as Cyclops. Fans hope this isn’t the end of the X-Men announcements as there is hope for Jackman to return as Wolverine alongside Halle Berry as Storm, Famke Janssen as Jean Grey, and Anna Paquin as Rogue.
One has to wonder why this upcoming Avengers movie, which features The Fantastic Four foe Doctor Doom as its title villain, has so many X-Men. Well, it appears that Avengers: Doomsday might be merging two iconic comic storylines to create an epic Marvel showdown.

‘Avengers: Doomsday’ Could Combine ‘Avengers vs. X-Men’ and ‘Time Runs Out’

In the lead-up to Avengers: Doomsday, a big question hanging over the film is what comics the film would draw from for inspiration. The Avengers combined The Avengers #1 from 1963 with The Ultimates comics from 2002. Avengers: Age of Ultron took its name from the 2013 Age of Ultron comic event but primarily crafted an original comic story lifted from elements from the late 1960s and early 1970s Marvel Comics. Avengers: Infinity War took its name from the Infinity War comic but was primarily an adaptation of 1991’s Infinity Gauntlet, The Thanos Quest, and 2013’s Infinity. Avengers: Secret Wars appears to draw from both 1985 and 2015’s Secret Wars comics, but that left Avengers: Doomsday’s status unknown.
With the X-Men casting news and what has been established about the Multiverse in the MCU, Avengers: Doomsday will likely merge elements from 2012’s Avengers vs. X-Men, ‘Time Runs Out,’ and the first issue of Secret Wars. This certainly isn’t the first time the idea of an Avengers movie becoming an Avengers vs. X-Men movie has come up. After Jonathan Majors was fired as Kang the Conqueror and before Avengers: The Kang Dynasty was renamed Avengers: Doomsday in July 2024, we theorized that the fifth Avengers movie might be called Avengers vs. X-Men, due to the high-concept premise being a major sell to general audiences. Our prediction was published on Feb. 29, 2024, and now, nearly a year later, it might be paying off.
Avengers vs. X-Men was Marvel’s big comic event of 2012 that saw the two Marvel teams fighting over what to do with the Phoenix Force, with the X-Men characters wanting to use it to restore the world’s mutant population after the Scarlet Witch had nearly wiped them out in House of M, while the Avengers wanted to destroy the Phoenix Force believing it was too dangerous to be wielded. Given that neither the X-Men nor the Phoenix Force exist in the MCU at this moment, the MCU’s way of pitting these two hero teams against each other is in a multiversal showdown. One is between the MCU sacred timeline Avengers and the X-Men from the 20th Century Fox Universe, one that Deadpool & Wolverine described as Earth 10005.

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The idea of two universes colliding in an all-out battle is precisely what happens in the aftermath of ‘Time Runs Out’ and the first issue of Secret Wars. Following a series of incursions and various realities being destroyed, only two universes remain: the primary 616 Marvel Comics Universe and the Ultimate Marvel Comics universe as Secret Wars #1 begins with a battle between the two realities for survival.
It appears that Avengers: Doomsday will adopt the idea of two universe incursions, leading to a battle between two distinct universes of heroes. In place of the 616 Marvel Comics vs. Ultimate Universe, the battle will be between the MCU 616 timeline and the Fox X-Men films of Earth 10005. This means Avengers: Doomsday will take the basic concept of Avengers vs. X-Men but merge it with the conflict motivation of ‘Time Runs Out’ and Secret Wars.
While the Avengers and X-Men Fight, The Fantastic Four Will Deal With Doctor Doom

What is interesting is that Avengers: Doomsday will not only be a showdown between two different universes, the MCU and the Fox X-Men Universe, but a third reality is at play in the story, that of The Fantastic Four from their MCU film, The Fantastic Four: First Steps. The forthcoming MCU entry establishes The Fantastic Four as taking place in their own reality, apart from the MCU and other realities glimpsed in Deadpool & Wolverine, Loki, The Marvels, and Doctor Strange in the Multiverse of Madness. Where do The Fantastic Four factor into the story of Avengers: Doomsday if it primarily focuses on the X-Men and Avengers fighting?
There is a good chance that Avengers: Doomsday will take a similar approach to Avengers: Infinity War, which splits the various lead characters into factions typically led by a key character: Captain America on Earth, Iron Man on Titan, and Thor going to Nidavellir. Doomsday could split the perspectives into three central teams/realities. The Avengers of 616, the X-Men of 10005, and The Fantastic Four of their currently undesignated reality. Suppose the Avengers and the X-Men are caught up fighting each other. In that case, that might put The Fantastic Four on their side mission that leaves them dealing with Doctor Doom, possibly in a race across time and space to see who can get to Loki first, as we theorized before this rumor online started to take hold.
With Doctor Doom being The Fantastic Four’s archenemy, that would make sense, as it makes Avengers: Doomsday also a semi-Fantastic Four movie that pits them against their iconic foe. Making The Fantastic Four the main team dealing with Doctor Doom also quells the early bad buzz from fans who were disappointed at rumors that the movie would downplay Doctor Doom and Reed Richards’ legendary comic rivalry. With Pedro Pascal getting the final chair before Robert Downey Jr., it seems apparent that Reed Richards and Doom will be tied together in Avengers: Doomsday.
Do We Now Know the Basic Plot of ‘Avengers: Doomsday’?

Gleaning what we can from the casting announcements, the previous films in the Marvel Cinematic Universe, and the comics, this is our theory for how Avengers: Doomsday might pan out.
The post-credits scene from Captain America: Brave New World had Tim Blake Nelson’s Leader tease that “the others are coming,” which is now meant to be the X-Men. Avengers: Doomsday will see an incursion between the Marvel Cinematic Universe and the X-Men reality that leads to a battle between two realities fighting for survival, with battles on multiple fronts between iconic heroes. Sam Wilson will assemble his team of Avengers, which now at least will consist of Shang-Chi, Black Panther, Thor, The Falcon, and Ant-Man, with more characters like She-Hulk, Captain Marvel, and Moon Knight possibly ready to be added. Shuri will likely also call on Namor for assistance, using his army to protect their reality, paying off Namor’s tease at the end of Black Panther: Wakanda Forever that the surface world would call upon them someday.
While the X-Men and Avengers forces battle it out for survival, The Fantastic Four and Doctor Doom will hop between realities to try to reach Loki, who sits at the edge of Time and Space as the God of Stories. Loki will likely take the role of Molecule Man or the Beyonders in the Secret Wars comic and Odin in Marvel Ultimate Alliance as a figure of great power whom Doctor Doom needs to rewrite reality. The Fantastic Four or another group of heroes might find themselves inside the Void and cross paths with the Thunderbolts, who have been trapped there since the end of their film (we’ve theorized about that previously).

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Eventually, the X-Men and the Avengers will realize they have been played and forced to fight one another as a distraction. The only way they can save their respective universe is to work together to stop Doctor Doom, but it will be too late. Doctor Doom will reach Loki’s throne, pull him off it, sit on it, and become God Emperor Doom, like in the Secret Wars comics. Doctor Doom will smash the various strands of reality together to create his own world: Battleworld. Like Avengers: Infinity War, Avengers: Doomsday will end on a cliffhanger with the villain winning and setting up the ambitious Avengers: Secret Wars, which will take place on Battleworld and have the various Marvel realities taking place alongside one another.
With all that laid out, Avengers: Doomsday’s seeming decision to adapt Avengers vs. X-Men and the first issue of Secret Wars, with some shades of the video game Marvel Ultimate Alliance thrown in, makes sense. It looks to be a Marvel crossover that can rival Avengers: Infinity War and Avengers: Endgame and allows the movie to not only be an Avengers movie but also an X-Men legacy sequel and give the series a proper farewell and also a loose Fantastic Four sequel with a Doctor Doom focus. Despite the claims that the MCU feels aimless during the Multiverse Saga, it all looks to be coming together rather nicely. Avengers: Doomsday will release in theaters on May 1, 2026.