Marvel Studios Announces 6 Major Villains Returning In Phase 6

Of the 27 cast members revealed for Avengers: Doomsday, quite a few are returning MCU villains.

Marvel Studios unveiled the heroes and villains line-up for its first Phase 6 Avengers film via a live stream earlier in the week (with more cast members still to be announced). 

Among the familiar names set to appear in the film, like Chris Hemsworth and Paul Rudd, were some surprising returns, such as X-Men cast members Patrick Stewart and James Marsden.

MCU Phase 6 Villains Lineup Revealed

Loki

After leading his Disney+ show to a conclusion in Season 2, Loki is making a surprising return in Phase 6.

While Loki was an antagonist (sometimes friend) in the Thor movies, he went through a redemptive arc in his Disney+ story, eventually becoming the God of Stories. 

This cemented Tom Hiddleston's character as a powerful figure in the Multiverse, and thus, he will probably be vital to the plot of Avengers: Doomsday.

Namor

Namor was introduced as the leader of the underwater nation of Talokan in Black Panther: Wakanda Forever. Unfortunately, he quickly becomes the story's antagonist after Wakanda and its alliance with the surface world threaten his nation's peace.

Tenoch Huerta is set to return as Namor in Avengers: Doomsday, but after his peace alliance with Shuri at the end of Black Panther: Wakanda Forever, it's unclear whether he'll return as a friend or foe.

Ghost

Hannah John-Kamen already has another MCU movie lined up as Ava Starr, aka Ghost, following 2025's Thunderbolts*, after being included in the Avengers: Doomsday cast list.

Ghost was introduced as the villain in Ant-Man and The Wasp. She sought to absorb energy from the Quantum Realm to cure her debilitating disease, which conflicted with Hope and Hank's plans to rescue Janet.

It remains to be seen what Ghost goes through in Thunderbolts* and which side she will be on at the end, but she is one of a few ex-Marvel villains reprising their roles for the Avengers film.

Sentry

Another character who will appear in Thunderbolts* prior to Avengers: Doomsday is Sentry (Lewis Pullman).

Audiences are yet to see what Sentry is capable of, but he's already being teased as a villain "stronger than all the Avengers rolled into one." Those who are familiar with the character from the comics will know Sentry possesses an array of powers, including flight, superhuman strength, speed, and senses.

Depending on how things go for Sentry at the end of Thunderbolts* he may become one of the Avenger's greatest threats in Doomsday, or could be one of their best allies.

Magneto

Ian McKellen's classic X-Men villain is entering the MCU in Phase 6. Magneto and Professor X have often been depicted as opposites who want the best for mutant kind but disagree on how to get it.

At times, this has made Magneto the X-Men's greatest villain; at others, he has been a powerful ally. McKellen's version of the character was last seen in X-Men: Days of Future Past, in which he helped the superhero team fight Bolivar Trask's Sentinels.

Whether Avengers: Doomsday will pick up with this version of the character or a different one from the Multiverse could determine how much of a villain Magneto is in the movie.

Mystique

Another long-time ally of Magneto and enemy of the X-Men is the shapeshifting blue mutant, Mystique.

Rebecca Romijn portrayed the character in the original Fox X-Men movies and will do so again in Avengers: Doomsday. Mystique died in X-Men: The Last Stand, making the 2026 Marvel movie the first time Romijn has appeared in the role in almost 20 years.

Mystique is set to appear in Avengers: Doomsday alongside Nightcrawler (Alan Cumming), marking an interesting reunion between them.

BONUS: Doctor Doom

While none of the characters above have confirmed whether they will continue to play into their villainous roots in Avengers 5, one character who is poised to be the big bad of the movie is Doctor Doom.

The legendary Marvel character will be played by none other than Iron Man actor Robert Downey Jr., who will appear in Phase 6 of the MCU now as a villain rather than a hero.

It was long suspected that Victor von Doom would appear in the MCU's Fantastic Four: First Steps in some capacity, but after Marvel Studios switched Avengers: The Kang Dynasty for Avengers: Doomsday, Doctor Doom's villainous arc became even more important to the Multiverse Saga.

Avengers: Doomsday is scheduled for release on May 1, 2026.