Marvel Studios has confirmed that a number of iconic villains from Marvel’s movie history will be returning to theMCUinAvengers: Doomsday. The Russo brothers' upcomingDoomsdayandSecret Warsare expected to be the biggest MCU movies in the franchise’s almost-two-decade-long continuity, with their massive casts rivaling those ofInfinity WarandEndgame. Marvel Studios confirmed the first27 actors cast inAvengers: Doomsdayat 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 inAvengers: 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.
8Bucky 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, inAvengers: Doomsday. His most recent appearance sees Bucky become a member of, and perhaps even the leader of, theMCU’s first Thunderbolts team, completing his redemption arc after breaking free of HYDRA’s conditioning and making amends inThe Falcon and the Winter Soldier.All the Thunderbolts team’s members have been confirmed to appear inDoomsday, except Taskmaster, so Bucky’s role will be crucial.
Bucky Barnes started his MCU careeras Steve Rogers' childhood best friend and ally following his transformation into Captain America. Bucky became the Winter Soldier after falling into HYDRA’s hands, buthe 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: Doomsdaywill 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.
7Namor
Tenoch Huerta Mejía Debuted As Namor In Black Panther: Wakanda Forever (2022)
Following recent unconfirmed allegations, it was unclear what the future held forTenoch Huerta Mejía’s Namor in the MCUafter his debut in 2022’sBlack 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 ofWakanda Forever, despite fighting for the protection of his own kingdom, and this ended with him entering into a truce with Letitia Wright’s Shuri, the new Black Panther.
Black Panther 2: 10 Biggest Differences Between Namor In The MCU & Comics
Namor has been around since the very beginning of Marvel, but the MCU film does take a few liberties with the mysterious mutant ruler.
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 inAvengers: Doomsdaycould spell tragedy for his underwater nation of Talokan, ashe would only join the surface-dwelling heroes in battle against Doctor Doom if something awful happened to his people.Doomsdaywill 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 toBlack Panther: Wakanda Foreverand could set Namor up for a very exciting future in the MCU.
6Bob’s Sentry
Lewis Pullman Debuts As Sentry In Thunderbolts* (2025)
WhileThunderboltsbrings together several characters from the MCU’s past, the Phase 5 movie also introduced a brand-new character in the form ofLewis Pullman’s “Bob,” a.k.a. the Sentry. Introduced to Marvel Comics in 2000’sThe 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.Thunderboltsputs 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 inAvengers: Doomsday.
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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’sAvengers: 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.
5John 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 inAvengers: Doomsdaywas actually introduced to the MCU as a legacy hero, asWyatt Russell’s John Walker was hired as the new Captain Americaafter 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.
Welp, There Goes My Thunderbolts* Theory About John Walker
While I did have a pretty cool theory for John Walker, the new Thunderbolts* trailer has hilariously debunked the idea (but it makes sense).
This controversial act forced the government to rid John Walker of the Captain America title, but Valentina Allegra de Fontaine transformed him into theUS Agent, enhanced by the super-soldier serumin his veins. Walker will seemingly be trying to do some good inThunderbolts*, 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 inAvengers: Doomsday.
4Ava 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 inAvengers: Doomsdayis Hannah John-Kamen’sAva Starr, a.k.a.Ant-Man and the Wasp’sphasing 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.
Ava Starr was working with Laurence Fishburne’s Bill Foster inAnt-Man and the Wasp. Foster has also been speculated to be returning after his recent appearances in the animatedWhat If…?series.
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 meansGhost 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 inAvengers: Doomsday, perhaps as a more bona fide hero, continuing her evolution and redemption. This will also reunite her withPaul Rudd’s Scott Lang, a.k.a. Ant-Man, which will surely create an entertaining moment between the pair.
3Loki
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’sThorandThe Avengersto savior and hero inThor: Ragnarok. He met his demise inInfinity War, but the escape of a variant inEndgameallowed 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 inLoki season 2.
Tom Hiddleston suggested he would be open to returning in the MCU’s future afterLokiseason 2, but Marvel Studios confirmed nothing until the officialAvengers: Doomsdaycast announcement.Loki’s involvement inDoomsdaysuggests Doctor Doom might target him to steal his power, with the former God of Mischief perhaps replacing the Beyonder or the Beyondersfrom Marvel Comics’Secret Warsevents.Loki will surely be central toAvengers: Doomsday’sstory, but this will evidently be as a bona fide hero, no longer as one of the MCU’s most terrifying villains.
2Raven 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’sX-Menfranchise,Rebecca Romijn played Mystique in the original trilogy of 2000’sX-Men, 2003’sX2and 2006’sX-Men: The Last Stand. Romijn last appeared as Mystique for a cameo in 2011’sX-Men: First Class, butAvengers: Doomsdaywill mark her first full appearance as the former villain in 20 years.Mystique was a staunch villain in Fox’s originalX-Mentrilogy, but the revised timeline transformed her into a hero.
I’m Convinced Avengers: Doomsday’s X-Men Cast Reveals Give The Movie The Perfect Chance To Use 1 Major Missing Story That All Of Fox’s Movies Avoided
Two of the biggest surprises in Avengers: Doomsday’s cast reveal have us thinking that one of Fox’s unexplored X-Men storylines can finally be seen.
It could be assumed that Mystique and other returning X-Men villains will be joining the heroes ofAvengers: Doomsdayto battle Doctor Doom, and Raven’s shape-shifting abilities will make her a formidable asset.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 inDoomsdayis hugely exciting, especially since this will mark thereturn of Fox’s mutants to live-action.
1Erik Lehnsherr’s Magneto
Ian McKellen Debuted As Magneto In X-Men (2000)
Mystique isn’t the only X-Men villain returning inAvengers: Doomsday, as she will also be joined byIan McKellen’s Erik Lehnsherr, a.k.a. Magneto. Magneto was featured as the primary antagonist for most of Fox’sX-Menfranchise, with McKellen playing the Master of Magnetism opposite Patrick Stewart’s Professor X in the originalX-Mentrilogy.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.
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Instead, it could be assumed thatIan 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’sX-Men: Days of Future Past, so could do the same inAvengers: Doomsday.Michael Fassbender did a wonderful job at portraying Magnetoafter McKellen, but we can’t wait to see Erik Lehnsherr’s original actor return alongside other classicX-Menactors.Avengers: Doomsdaymight be bringing back several villains, but they may all be no match for Robert Downey Jr.’s Doctor Doom.
