Marvel Studios has confirmed that a number of iconic villains from Marvel’s movie history will be returning to the MCU in Avengers: Doomsday. The Russo brothers’ upcoming Doomsday and Secret Wars are expected to be the biggest MCU movies in the franchise’s almost-two-decade-long continuity, with their mᴀssive casts rivaling those of Infinity War and Endgame. Marvel Studios confirmed the first 27 actors cast in Avengers: Doomsday at the end of March 2025, and this included eight returning villains from a variety of chapters in Marvel’s live-action movie history.

While several formidable villains will be returning in Avengers: Doomsday, many of them have since been transformed into antiheroes or even bona fide superheroes. A few of them have joined forces as the Thunderbolts, while others joined the X-Men under the umbrella of 20th Century Fox. One has even gone on to become the protector of the entire multiverse, so it seems these villains will be returning to the MCU to face an even stronger supervillain with much more nefarious intentions: Robert Downey Jr.’s Doctor Doom.

8

Bucky Barnes’ Winter Soldier

Sebastian Stan Debuted As Bucky Barnes In Captain America: The First Avenger (2011)

Sebastian Stan will become one of the MCU’s longest-running characters thanks to his appearance as Bucky Barnes, a.k.a. the Winter Soldier, a.k.a. the White Wolf, in Avengers: Doomsday. His most recent appearance sees Bucky become a member of, and perhaps even the leader of, the MCU’s first Thunderbolts team, completing his redemption arc after breaking free of HYDRA’s conditioning and making amends in The Falcon and the Winter Soldier. All the Thunderbolts team’s members have been confirmed to appear in Doomsday, except Taskmaster, so Bucky’s role will be crucial.

Bucky Barnes started his MCU career as Steve Rogers’ childhood best friend and ally following his transformation into Captain America. Bucky became the Winter Soldier after falling into HYDRA’s hands, but he was broken free of this spell by Steve Rogers and the Wakandans, allowing him to become a true hero and, unbelievably, even a Congressman, though it doesn’t seem like this will last long. Avengers: Doomsday will give Bucky a central role as the leader of the Thunderbolts, but some theories have unfortunately suggested the former villain might not survive the MCU’s Multiverse Saga.

7

Namor

Tenoch Huerta Mejía Debuted As Namor In Black Panther: Wakanda Forever (2022)

Following recent unconfirmed allegations, it was unclear what the future held for Tenoch Huerta Mejía’s Namor in the MCU after his debut in 2022’s Black Panther: Wakanda Forever. Namor was one of Marvel Comics’ original superheroes back in 1939, alongside Captain America and the Human Torch android, so it is essential that he gets developed more. Namor was featured as the primary antagonist of Wakanda Forever, despite fighting for the protection of his own kingdom, and this ended with him entering into a truce with Leтιтia Wright’s Shuri, the new Black Panther.

Namor has always been depicted as an antihero in Marvel Comics, and it seems this will be continuing in the MCU, too. Namor’s role in Avengers: Doomsday could spell tragedy for his underwater nation of Talokan, as he would only join the surface-dwelling heroes in battle against Doctor Doom if something awful happened to his people. Doomsday will likely see Namor team up with Shuri’s Black Panther and M’Baku, the new King of Wakanda, which will be the perfect follow-up to Black Panther: Wakanda Forever and could set Namor up for a very exciting future in the MCU.

6

Bob’s Sentry

Lewis Pullman Debuts As Sentry In Thunderbolts* (2025)

While Thunderbolts* brings together several characters from the MCU’s past, the Phase 5 movie also introduced a brand-new character in the form of Lewis Pullman’s “Bob,” a.k.a. the Sentry. Introduced to Marvel Comics in 2000’s The Sentry #1, Robert Reynolds is an extremely powerful super-soldier who harbors the power of a million exploding suns, but also has a dark alter ego known as the Void. Thunderbolts* puts the Void front-and-center as a villain threatening New York City and the world by spreading his darkness, which could set him up as a significant threat in Avengers: Doomsday.

The Sentry has the opportunity to be the MCU’s most powerful new superhero, but it seems that this debut will be tainted by the emergence of his dark half. The Void is a huge danger to the Thunderbolts in 2025, but “Bob” could end up joining their ranks to take down Valentina Allegra de Fontaine, and could be featured as an official member of the Thunderbolts team come 2026’s Avengers: Doomsday. This would set up a bright future for the Sentry in the MCU, both as a Thunderbolt and as an independent hero, which is very exciting.

5

John Walker’s US Agent

Wyatt Russell Debuted As US Agent In The Falcon & The Winter Soldier (2021)

Another member of Marvel Studios’ first Thunderbolts team confirmed to be returning in Avengers: Doomsday was actually introduced to the MCU as a legacy hero, as Wyatt Russell’s John Walker was hired as the new Captain America after Steve Rogers’ retirement. Sam Wilson donated the Captain America shield to the Smithsonian, but the United States government betrayed him by making Walker the Star-Spangled-Man. Nevertheless, Walker’s true colors soon presented themselves, though, as he used Captain America’s shield to brutally murder a member of the Flag Smashers in broad daylight.

This controversial act forced the government to rid John Walker of the Captain America тιтle, but Valentina Allegra de Fontaine transformed him into the US Agent, enhanced by the super-soldier serum in his veins. Walker will seemingly be trying to do some good in Thunderbolts*, but it will be hard to escape from his violent and morally-questionable past. As a dark mirror to Captain America, it will be great to see US Agent reunite with Sam Wilson’s Captain America and Bucky Barnes’ Winter Soldier in Avengers: Doomsday​​​​​​​.

4

Ava Starr’s Ghost

Hannah John-Kamen Debuted As Ghost In Ant-Man & The Wasp (2018)

The final former villain included in the MCU’s first Thunderbolts team who was confirmed to be returning in Avengers: Doomsday is Hannah John-Kamen’s Ava Starr, a.k.a. Ant-Man and the Wasp’s phasing antagonist, Ghost. Ghost wanted to steal the Quantum Realm energy inside Janet van Dyne to solve her phasing problem and make herself “normal,” but didn’t realize that van Dyne could fix her problem safely upon her return. Having fought as an elite SHIELD warrior for years, Ghost is a very powerful character, and it’ll be great to see her personality explored more.

While Janet van Dyne helped quell the unpredictability of Ghost’s phasing, Ava Starr has retained her abilities, but now has more control over them. This means Ghost is the most unique and interesting member of the Thunderbolts team, as she has actual superpowers among a group of super-soldiers. It will be fantastic to see Ghost return in Avengers: Doomsday, perhaps as a more bona fide hero, continuing her evolution and redemption. This will also reunite her with Paul Rudd’s Scott Lang, a.k.a. Ant-Man, which will surely create an entertaining moment between the pair.

3

Loki

Tom Hiddleston Debuted As Loki In Thor (2011)

Tom Hiddleston’s MCU character has perhaps had the biggest transformation in the entire franchise, as he went from scheming and manipulative supervillain in Phase 1’s Thor and The Avengers to savior and hero in Thor: Ragnarok. He met his demise in Infinity War, but the escape of a variant in Endgame allowed him to embark on a new redemption arc in his solo Multiverse Saga series. This new Loki helped take down Kang variant He Who Remains and restructure the Time Variance Authority to save the multiverse, even becoming the multiverse’s protector in Loki​​​​​​​ season 2.

Tom Hiddleston suggested he would be open to returning in the MCU’s future after Loki season 2, but Marvel Studios confirmed nothing until the official Avengers: Doomsday cast announcement. Loki’s involvement in Doomsday suggests Doctor Doom might target him to steal his power, with the former God of Mischief perhaps replacing the Beyonder or the Beyonders from Marvel Comics’ Secret Wars events. Loki will surely be central to Avengers: Doomsday’s story, but this will evidently be as a bona fide hero, no longer as one of the MCU’s most terrifying villains.

2

Raven Darkhölme’s Mystique

Rebecca Romijn Debuted As Mystique In X-Men (2000)

Before Jennifer Lawrence took over the role of the shape-shifting mutant in the revised timeline of 20th Century Fox’s X-Men franchise, Rebecca Romijn played Mystique in the original trilogy of 2000’s X-Men, 2003’s X2 and 2006’s X-Men: The Last Stand. Romijn last appeared as Mystique for a cameo in 2011’s X-Men: First Class, but Avengers: Doomsday will mark her first full appearance as the former villain in 20 years. Mystique was a staunch villain in Fox’s original X-Men trilogy, but the revised timeline transformed her into a hero.

It could be ᴀssumed that Mystique and other returning X-Men villains will be joining the heroes of Avengers: Doomsday to battle Doctor Doom, and Raven’s shape-shifting abilities will make her a formidable ᴀsset. It remains to be seen how much of Rebecca Romijn’s upcoming performance will be influenced by Jennifer Lawrence’s interpretation of Mystique, but it’s possible her return could present a very different version of the character than she last played in 2006. Nevertheless, Mystique’s return in Doomsday is hugely exciting, especially since this will mark the return of Fox’s mutants to live-action.

1

Erik Lehnsherr’s Magneto

Ian McKellen Debuted As Magneto In X-Men (2000)

Mystique isn’t the only X-Men villain returning in Avengers: Doomsday, as she will also be joined by Ian McKellen’s Erik Lehnsherr, a.k.a. Magneto. Magneto was featured as the primary antagonist for most of Fox’s X-Men franchise, with McKellen playing the Master of Magnetism opposite Patrick Stewart’s Professor X in the original X-Men trilogy. Over a decade after he last played Magneto, it will be fantastic to see Ian McKellen reprise the role in the MCU’s Phase 6, but, once again, this likely won’t be in the capacity of a true villain.

Instead, it could be ᴀssumed that Ian McKellen’s Magneto will join Professor X and the X-Men to fight Doctor Doom and protect his reality of Earth-10005. He already joined the X-Men to fight the Sentinels in 2014’s X-Men: Days of Future Past, so could do the same in Avengers: Doomsday. Michael Fᴀssbender did a wonderful job at portraying Magneto after McKellen, but we can’t wait to see Erik Lehnsherr’s original actor return alongside other classic X-Men actors. Avengers: Doomsday might be bringing back several villains, but they may all be no match for Robert Downey Jr.’s Doctor Doom.

Upcoming MCU Movies

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  Thunderbolts*

  Release Date

  
  May 2, 2025
  

  
  
  
  

  
  

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  The Fantastic Four: First Steps

  Release Date

  
  July 25, 2025
  

  
  
  
  

  
  

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  Avengers: Doomsday (2026)

  
  
  
  
  

  
  

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  Spider-Man: Brand New Day

  Release Date

  
  July 31, 2026
  

  
  
  
  

  
  

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  Avengers: Secret Wars

  Release Date

  
  May 7, 2027
  

  
  
  
  

  
  

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