The Marvel Cinematic Universe is undergoing another seismic shift. As Avengers: Doomsday heads toward its 2026 release, longtime cast members are addressing their absence—and new imagery has fans wondering if Captain Marvel and Thor have already fallen to Robert Downey Jr.’s Doctor Doom.
Anthony and Joe Russo are back in the director’s chairs for Avengers: Doomsday, marking their return after Avengers: Infinity War (2018) and Avengers: Endgame (2019). The project has been retooled to center on Doctor Doom, with Downey Jr. stepping back into the franchise in an unexpected role.
In early 2025, Marvel unveiled its enormous ensemble through a “chair reveal” livestream featuring Sebastian Stan, Paul Rudd, Simu Liu, Florence Pugh, Tom Hiddleston, Chris Hemsworth, Kelsey Grammer, and James Marsden. The announcement also confirmed the reappearance of legacy X-Men actors Ian McKellen, Rebecca Romijn, Patrick Stewart, and Alan Cumming.
Fans have speculated about other returning stars such as Brie Larson, Karen Gillan, Tessa Thompson, and Dominique Thorne, though Marvel has yet to make those additions official. By late 2025, Pedro Pascal had completed his work as Reed Richards, following his introduction in The Fantastic Four: First Steps (2025), while Cumming confirmed that Nightcrawler had wrapped his scenes—indicating the film’s advanced stage of production.
Notably missing is Mark Ruffalo. The actor, who has played the Hulk since 2012’s The Avengers, spoke about his absence on The Tonight Show Starring Jimmy Fallon, saying, “They decided that it was better to get rid of me than for me to tell the end of the next movie.” Ruffalo will next appear in Destin Daniel Cretton’s Spider-Man: Brand New Day (2026).
Following Ruffalo’s comments, both Benedict Cumberbatch and Brie Larson addressed their own uncertain involvement. During The View, Larson fielded the question, “Is there any chance that we will see Captain Marvel in the upcoming Avengers: Doomsday?” Her reply—“Thank you for asking, and you know I can’t answer”—did little to quiet speculation. She previously avoided confirming her MCU future in 2024 and later sparked new theories in 2025 by posting a photo featuring the words “AVENGE” and “DANVERS.”
A recently unveiled image has only fueled fan theories. The HD promo art, shared by ComicBookMovie after its debut at the Walt Disney Studios Marketing Expo in Shanghai, shows Doctor Doom’s armor adorned with two circular fasteners—one resembling Captain Marvel’s emblem, the other echoing Mjolnir’s shape. The design has led many to believe Doom has already confronted and possibly defeated alternate versions of both heroes across the Multiverse.
While those details may simply be aesthetic, their placement has fueled talk that Downey Jr.’s Doom is poised to become the MCU’s most formidable antagonist yet. Larson last appeared in The Marvels (2023), which ended with Carol Danvers promising to find Monica Rambeau, making Carol’s absence all the more curious.
The changes arrive as Marvel Studios recalibrates its larger strategy for Phase Six. The Fantastic Four: First Steps opened to strong numbers but fell sharply in its second weekend, signaling that even major titles face audience fatigue. Kevin Feige and the Russo brothers have since teased Avengers: Doomsday and Avengers: Secret Wars (2027) as a creative relaunch centered around the X-Men.
With Downey Jr. leading a sprawling cast that spans multiple Marvel eras, Avengers: Doomsday may serve as both a unifier and a turning point for the MCU when it premieres on December 18, 2026.
