For years, the old X-Men movies existed beside the Marvel Cinematic Universe without needing an official bridge between them. Deadpool & Wolverine changed that by giving Wade Wilson’s reality a number: Earth-10005.
Now that number suddenly matters.
New footage added to Avengers: Endgame Encore shows the TVA detecting an incursion involving Earth-10005 and another reality, Earth-1127, as the wider multiverse begins collapsing. That would be a fun Easter egg on its own—except Marvel has already confirmed that Patrick Stewart, Ian McKellen, James Marsden, Rebecca Romijn, Alan Cumming and Kelsey Grammer are appearing in Avengers: Doomsday.
In other words, Earth-10005 may be the explanation for why the X-Men are in an Avengers movie at all.
Spoilers for Deadpool & Wolverine and Endgame Encore follow.
What exactly is Earth-10005?
The simple answer: it is the universe associated with the Fox-era X-Men movies and Deadpool.
Deadpool & Wolverine explicitly identifies Wade Wilson’s home reality as Earth-10005, separate from Earth-616, the main MCU universe containing the Avengers. Wade briefly travels to Earth-616 hoping to join the Avengers before returning home.
Earth-10005 therefore broadly connects the cinematic world built through movies including X-Men, X2, X-Men: The Last Stand, the First Class era and the first two Deadpool films.
There is a complication: the X-Men movie timeline was rewritten by the time-travel events of X-Men: Days of Future Past, and the franchise was never especially consistent about its chronology. So Earth-10005 is best understood as Marvel’s current multiversal home for that Fox X-Men/Deadpool continuity, rather than evidence that every continuity problem in those movies has suddenly been solved.
That distinction becomes important in Doomsday because Marvel isn’t simply introducing brand-new MCU versions of Cyclops and Magneto.
It is bringing back actors audiences already associate with that older cinematic world.
Deadpool & Wolverine already saved Earth-10005 once
Earth-10005 was in trouble before Doomsday.
In Deadpool & Wolverine, TVA official Mr. Paradox tells Wade that his universe is deteriorating because its “anchor being,” Hugh Jackman’s original Wolverine, died during the events associated with Logan. Paradox plans to accelerate that process using the Time Ripper rather than allowing the timeline to fade naturally.
Wade refuses to abandon his friends and searches the multiverse for another Wolverine. He eventually brings a Logan variant back with him, and together they stop Cassandra Nova and destroy the Time Ripper.
By the end of the movie, Earth-10005 survives and the new Wolverine remains there with Wade.
That seemed like a happy ending.
Endgame Encore now suggests it was only temporary.
The new Encore scene puts the X-Men world on a collision course
The crucial new sequence takes place inside the TVA.
Mobius and Ouroboros detect Earth-10005 and Earth-1127 moving toward an incursion. The situation quickly escalates as more collisions appear throughout the multiverse; GamesRadar reports that the sequence eventually shows thousands of incursions unfolding.
An incursion, in Marvel terminology, is essentially a catastrophic collision between realities. Marvel’s comics used the concept extensively in Jonathan Hickman’s Avengers and New Avengers storyline leading into 2015’s Secret Wars: when two parallel Earths collide, both universes face destruction unless one Earth is eliminated.
That suddenly gives the returning X-Men a much stronger motivation than “Marvel wanted a crossover.”
Their home may be dying.
It also matches what Marvel Studios president Kevin Feige has already said about Doomsday. Discussing the film, he described a threat involving “worlds literally colliding” and specifically mentioned interactions between the Avengers, Fantastic Four and X-Men.
Disney went even further at San Diego Comic-Con 2026, officially describing Doomsday as bringing heroes from three distinct universes onto a “deadly collision course.”
Earth-10005 now looks like one of those three.
The X-Men are not simply moving into Earth-616
This is the most important difference.
It would have been easy for Marvel to use the multiverse as a doorway: open a portal, bring Patrick Stewart’s Professor X and Ian McKellen’s Magneto into the MCU, and start the team-up.
The Earth-10005 storyline potentially makes the crossover much more personal.
If their reality is facing destruction, the X-Men may enter Doomsday trying to save their own universe, not necessarily help the Avengers protect Earth-616.
That creates room for conflict.
Marvel has already shown in Doctor Strange in the Multiverse of Madness that protecting one reality can threaten another. If Earth-10005 can survive only at the expense of another world, Xavier, Magneto, Cyclops and the Avengers may initially have completely different ideas about what “saving the universe” actually means.
That possibility would also help explain why Doomsday footage has shown Marvel heroes from different worlds confronting one another rather than immediately forming one enormous team.
What remains unknown is Earth-1127. Marvel has not yet publicly explained whose universe that number represents, so connecting it to a particular existing Marvel franchise would currently be speculation.
Doomsday may be the ending of the Fox X-Men universe
There is another reason Earth-10005 matters beyond Doomsday itself.
Marvel Studios is developing its own future X-Men movie, meaning Patrick Stewart and Ian McKellen’s generation is unlikely to function as the permanent MCU version of the team.
Feige has openly acknowledged the significance of revisiting the actors connected to the movies where his own Marvel career began. Discussing Doomsday, he said Deadpool & Wolverine “scratched the surface” and that Marvel is now going much deeper into those characters.
That makes Earth-10005 potentially more than an Easter egg.
It gives Marvel a way to celebrate the Fox X-Men films while also confronting the fact that their universe cannot remain separate forever as the Multiverse Saga approaches Secret Wars.
The Avengers have Earth-616. The Fantastic Four originate from their own reality. The classic X-Men have Earth-10005.
Avengers: Doomsday appears to be asking what happens when those worlds can no longer peacefully coexist.
And suddenly, that strange number first highlighted in Deadpool & Wolverine may be one of the most important pieces of Marvel’s entire endgame.
Avengers: Doomsday opens in theaters on December 18, 2026.
