Robert Downey Jr.‘s Doctor Doom will be using a powerful weapon against the X-Men in Marvel’s Avengers: Doomsday.
Multiple leaks during production revealed that a Sentinel was destroyed in front of the X-Mansion. In the Marvel comics, Sentinels were created to hunt, capture, or eliminate mutants.
According to insider Daniel Richtman, Downey Jr.’s Doctor Doom will reportedly be using Sentinels to fight the X-Men in Avengers: Doomsday.


We have also reported that the Russo brothers have filmed an “epic fight” scene featuring the Avengers and the Fantastic Four battling the X-Men, who are seen in comic-accurate suits.
An insider confirms that in Avengers: Doomsday‘s X-Men universe, a team of Avengers already exists: a variant of Iron Man, a variant of Black Panther, Binary (Maria Rambeau), and Hank Pym, who is known as Giant in this universe.
Most recently, a leak from QuidVacuo revealed that in Avengers: Doomsday, Gambit’s (Deadpool & Wolverine) universe is the same one Monica Rambeau arrived in during the post-credits scene of The Marvels.

Directed by Russo brothers from a screenplay by their longtime collaborator, Stephen McFeely. Newton Thomas Sigel (Bohemian Rhapsody, X-Men: Days of Future Past) will be the cinematographer.
In Avengers: Doomsday, the MCU begins the beginning of the end. As the multiverse nears total collapse, the Avengers assemble to face their greatest challenge yet—incursions, catastrophic collisions between realities that could destroy the entire multiverse. Earth’s Mightiest Heroes must race against time to save their reality while confronting the powerful figure behind it all—Victor Von Doom (Downey Jr.).
The official cast members of the film include Downey Jr. as Doctor Doom, Paul Rudd as Ant-Man, Simu Liu as Shang-Chi, Tom Hiddleston as Loki, Florence Pugh as Yelena Belova, Danny Ramirez as Falcon, Sebastian Stan as Bucky Barnes, Winston Duke as M’Baku, Chris Hemsworth as Thor, Letitia Wright as Black Panther, Tenoch Huerta Mejía as Namor, Anthony Mackie as Captain America, David Harbour as Red Guardian, Wyatt Russell as U.S. Agent, and Hannah John-Kamen as Ghost. Ian McKellen as Magneto, Patrick Stewart as Professor X, Rebecca Romijn as Mystique, James Marsden as Cyclops, Kelsey Grammer as Beast, Alan Cumming as Nightcrawler, and Channing Tatum as Gambit. Pedro Pascal as Reed Richards (Mr. Fantastic), Vanessa Kirby as Sue Storm (Invisible Woman), Joseph Quinn as Johnny Storm (Human Torch), Ebon Moss-Bachrach as Ben Grimm (The Thing), and Lewis Pullman as Sentry.
Marvel President Kevin Feige revealed at CinemaCon 2025 that Avengers: Doomsday will focus on the Avengers, Wakandans, Fantastic Four, the New Avengers (Thunderbolts), and the original X-Men all uniting to fight Doctor Doom (Downey Jr.).
During The Hot Mic podcast, Jeff Sneider revealed a list of unannounced cast members reportedly appearing in Avengers: Doomsday. The list includes:
- Mark Ruffalo as Bruce Banner / Hulk
- Benedict Wong as Wong
- Brie Larson as Captain Marvel (Carol Danvers)
- Hayley Atwell as either Captain Carter (from What If…?) or Peggy Carter
- Don Cheadle as James Rhodes / War Machine
- Karen Gillan as Nebula
- Jeremy Renner as Clint Barton / Hawkeye
- Iman Vellani as Kamala Khan / Ms. Marvel
- Danai Gurira as Okoye
- Tessa Thompson as Valkyrie
- Ke Huy Quan as Ouroboros
- Teyonah Parris as Monica Rambeau / Photon
- Will Poulter as Adam Warlock (confirmed in other reports)
- Dominique Thorne as Riri Williams / Ironheart
- Xochitl Gomez as America Chavez
- Sophia Di Martino, possibly as Sylvie or another character from Loki
- Tatiana Maslany as She-Hulk (Jennifer Walters)
- Yahya Abdul-Mateen II as Wonder Man
- Kathryn Newton as Cassie Lang / Stature
- Wunmi Mosaku as Hunter B-15
- Lashana Lynch as Captain Marvel (Maria Rambeau)
- Famke Janssen as Jean Grey (confirmed return of the original X-Men actress)
- Halle Berry as Storm (confirmed return of the original X-Men actress)
- Kai Zen Aspilla as Phyla-Vell
- Owen Wilson as Mobius M. Mobius
- Chris Pratt as Peter Quill / Star-Lord
- Samuel L. Jackson as Nick Fury
- Charlize Theron as Clea
- Benedict Cumberbatch as Doctor Strange
- Chris Evans as Steve Rogers / Captain America (rumored return)
- Bradley Cooper as the voice of Rocket Raccoon
- Vin Diesel as the voice of Groot
The film is produced by Feige, Louis D’Esposito, and Russo Brothers will produce through their AGBO banner.
Avengers: Doomsday is set to release in the United States on December 18, 2026.
Source: Daniel Richtman/X