Robert Downey Jr.’s Doctor Doom could easily take down some of the most powerful heroes in the MCU to prove his strength in 2026’s upcoming Avengers: Doomsday. After playing Tony Stark’s Iron Man for over a decade in the Infinity Saga, Robert Downey Jr. will now be returning to the MCU as Victor Von Doom, one of Marvel Comics’ most powerful and notable supervillains. Doctor Doom will have had no set-up prior to the Russo brothers’ Avengers: Doomsday, so he’ll need to make a strong first impression on the MCU.

Marvel Studios confirmed the first 27 actors cast in Avengers: Doomsday at the end of March, including members of the Avengers, the Thunderbolts, the X-Men, the Fantastic Four and Robert Downey Jr. himself. While there are many more actors that are still expected to be confirmed to be returning in Doomsday, surely not all of their MCU heroes will survive the events of the Phase 6 crossover. In fact, I reckon at least eight returning Marvel characters will meet their demise in Avengers: Doomsday, if not many more.

8

James Marsden’s Cyclops

James Marsden Debuted As Cyclops In 2000’s X-Men

James Marsden’s return as Scott Summer’s Cyclops 20 years after he was unceremoniously killed off in 2006’s X-Men: The Last Stand is hugely exciting. Marsden will likely be reprising his role from 20th Century Fox’s X-Men franchise, with Earth-10005 likely being revisited after the events of X-Men: Days of Future Past and ᴅᴇᴀᴅpool & Wolverine. While it would be a shame for Marsden’s Cyclops to be killed off in his next live-action appearance, just as he was in his last, it seems likely that his entire universe will be targeted by Doctor Doom.

If Doctor Doom targets Earth-10005, perhaps during his quest to destroy other worlds in an effort to thwart incursions from eradicating the multiverse, Cyclops would be one of many characters coming into his crosshairs. James Marsden’s version of Scott Summers deserves a huge amount of redemption in the MCU, as he was wasted, neglected and sidelined time and again in Fox’s X-Men franchise. Marvel Studios has the perfect opportunity to give him more substance, but it seems very likely Cyclops will be killed by Doctor Doom, allowing the villain to make a clear and fast impact.

7

Alan Cumming’s Nightcrawler

Alan Cumming Debuted As Nightcrawler In 2003’s X2: X-Men United

Alan Cumming is perhaps the most surprising actor confirmed to be returning in Avengers: Doomsday, so far, at least. Alan Cumming played Kurt Wagner’s Nightcrawler on only one occasion, back in 2003’s X2: X-Men United, where he was introduced as one of the mutants being controlled by William Stryker to orchestrate an attack on the President of the United States and bring the X-Men into his firing line. Kodi Smit-McPhee took over the role of Nightcrawler in the revised timeline, so there’s perhaps only one reason that Alan Cumming’s older version of the hero would be brought back.

Doctor Doom and Nightcrawler have battled before in Marvel Comics, though only when the latter was an official member of the X-Men. Avengers: Doomsday might reintroduce Fox’s X-Men team with Nightcrawler in the line-up, even though the teleporting hero was missing from X-Men: The Last Stand and X-Men: Days of Future Past. Nightcrawler’s return with Alan Cumming now in his 60s can only mean one thing, and it would be a fantastic emotional punch for the beloved X-Men hero to be killed by Robert Downey Jr.’s new supervillain.

6

David Harbour’s Red Guardian

David Harbour Debuted As Red Guardian In 2021’s Black Widow

Alexei Shostakov’s Red Guardian has become one of the most entertaining and joyous new additions to the MCU following his debut in 2021’s Black Widow. Thunderbolts* has made him a main character and a member of the MCU’s newest team, and he’ll return as a member of the Thunderbolts in Avengers: Doomsday, but this could end very badly for David Harbour’s powerful new super-soldier. In the same way that his surrogate daughter, Natasha Romanoff, sacrificed her life in Avengers: Endgame, Alexei Shostakov could do the same in Doomsday.

Red Guardian will be returning alongside his other surrogate daughter, Florence Pugh’s Yelena Belova. It would be a very powerful and poignant moment to have Shostakov sacrifice himself to save his daughter, perhaps handing himself over to Doctor Doom in exchange for Yelena Belova’s life. It would be a shame to lose David Harbour in the MCU, as he is a remarkable talent in both drama and comedy, but his departure from the MCU in Avengers: Doomsday could be given a very emotional and relatable significance.

5

Rebecca Romijn’s Mystique

Rebecca Romijn Debuted As Mystique In 2000’s X-Men

While Jennifer Lawrence took on the role of Mystique in Fox’s revised X-Men timeline, and gave the shape-shifting mutant more personality and substance, it was Rebecca Romijn who originated the role in the original X-Men trilogy. It makes sense that Marvel Studios is bringing back the older, classic X-Men cast for Avengers: Doomsday, so it will be fantastic to see Romijn reprise the role of Raven Darkhölme. However, it doesn’t seem likely that this will become a permanent return, especially since Marvel Studios is gearing up to reinvent the X-Men team in the MCU.

The fact that a new iteration of X-Men will soon be debuting in the MCU, perhaps with a much younger cast, means it’s likely most of the returning X-Men actors from 20th Century Fox’s franchise will not survive the MCU’s Phase 6. This includes Rebecca Romijn’s Mystique, who was last seen being cured of her mutant abilities in X-Men: The Last Stand, though this “cure” was teased to be temporary. Mystique might return as an official member of the X-Men team to battle Doctor Doom, which could lead her right to her shocking death.

4

Ian McKellen’s Magneto

Ian McKellen Debuted As Magneto In 2000’s X-Men

Another original X-Men villain who could be returning in Avengers: Doomsday as a hero and possible X-Men member is Ian McKellen’s original version of Magneto, the Master of Magnetism. Michael Fᴀssbender did a fantastic job at filling McKellen’s shoes, but it will be incredible to see McKellen reprise the role of Magneto, especially alongside other members of the original X-Men trilogy. However, Ian McKellen is now 85 years old, so it wouldn’t be a surprise to see this older and wiser Magneto lose his life in Avengers: Doomsday.

This would create a void in the MCU that a new Magneto actor could fill in the MCU’s X-Men reboot or beyond. Of course, it will be emotional to have Doctor Doom kill off Ian McKellen’s Erik Lehnsherr, but it would make sense for the Russo brothers’ upcoming crossover projects to bid a final and fond farewell to this iteration of Magneto. Marvel Studios needs to think about this – Doctor Doom wears a metal suit of armor, which should make it easy for Magneto to beat him, but Robert Downey Jr.’s villain’s incredible power must be a match for Magneto.

3

Patrick Stewart’s Professor X

Patrick Stewart Debuted As Professor X In 2000’s X-Men

Similarly to Ian McKellen, Patrick Stewart has also been confirmed to be returning as Charles Xavier’s Professor X, 26 years after he first appeared as the telepathic mutant in 2000’s X-Men. Stewart has already appeared as a Professor X variant in the MCU, as he was a member of Earth-838’s Illuminati in Doctor Strange in the Multiverse of Madness, though Avengers: Doomsday will seemingly revisit his original character from Fox’s X-Men timeline. Avengers: Doomsday may take place in the time between Days of Future Past and Logan, meaning Professor X will still be alive.

If Patrick Stewart is returning as Fox’s original Professor X, it would be amiss to kill him off in Avengers: Doomsday, as he will need to embark on Logan’s narrative. However, Logan could have been set in an alternate timeline, while Patrick Stewart could also be returning as another variant of his formidable X-Men hero, so Doctor Doom could still easily take him down in the MCU’s Phase 6. Doctor Doom wiping out Earth-10005 would clearly kill Professor X, while it would also be a huge power move for Doom to take down the leader of the X-Men alone.

2

Chris Hemsworth’s Thor

Chris Hemsworth Debuted As Thor In 2011’s Thor

It would make sense for any number of returning X-Men characters to be killed by Doctor Doom in Avengers: Doomsday, but some of the MCU’s own heroes might also be in the firing line. Endgame saw Steve Rogers, Tony Stark and Natasha Romanoff sacrifice their lives to save the universe from Thanos, and Doomsday could see Chris Hemsworth’s Thor do the same to save the entire multiverse. After Thor: Love and Thunder got a pretty poor reception, there has been speculation that Thor could be departing the MCU, and it would make sense for this to happen in Phase 6.

Chris Hemsworth has been central to the MCU ever since his debut back in Phase 1, though Marvel Studios has never really got Thor right in the MCU. He is currently the only MCU hero to get four solo movies, and has appeared in all four Avengers projects. Hemsworth was also the first actor confirmed to be returning in Avengers: Doomsday, but his upcoming reprisal could spell bad news for the God of Thunder. This could set up a much-wanted Valhalla-set storyline for Thor 5, and create some huge conflict for the MCU’s other heroes on Earth.

1

Loki

Tom Hiddleston Debuted As Loki In 2011’s Thor

Avengers: Doomsday became even more exciting for die-hard MCU fans when Tom Hiddleston was confirmed to be returning as former God of Mischief Loki, as the crossover could now reunite Loki with his long-lost brother, Thor. Beyond that, however, Loki’s return in Doomsday makes a lot of sense after the ending of Loki season 2, which saw Loki replace He Who Remains and the Temporal Loom to become the guardian of the multiverse. Loki has an incomprehensible amount of power, and Doctor Doom will surely want this for himself.

Popular theories suggest that Loki could take the place of the Beyonders from Marvel Comics’ Secret Wars event from 2015. Doctor Doom stole the Beyonders’ power to make him strong enough to build Battleworld after incursions destroyed the multiverse, and this could easily play out in the MCU’s Avengers: Doomsday if Doctor Doom steals Loki’s incredible new power. This act may mark Loki’s demise yet again, the latest in a long line, though it’s unclear what the future really holds for Tom Hiddleston after the MCU’s Phase 6.

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  May 2, 2025
  

  
  
  
  

  
  

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  The Fantastic Four: First Steps

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