Four iconic superhero actors will make their way into the MCU for the first time when Marvel Studios' Avengers: Doomsday makes its 2026 debut. In March 2025, Marvel confirmed Doomsday's first 27 cast members in a five-hour live stream event, teasing just part of the massive group of characters who will star in next Avengers movie.
Coming out on May 1, 2026, Doomsday will bring the Avengers, X-Men, Fantastic Four, and more together for an interdimensional brawl against Robert Downey Jr.'s Doctor Doom. While Downey and plenty of other MCU regulars will lead the way in this cast full of megastars, a few actors will reprise their legacy roles under the Marvel Studios banner - a change of pace from when they were last seen.
4 MCU Newcomers Debuting in Avengers: Doomsday
Ian McKellen - Magneto
Opposite Sir Patrick Stewart's Professor X throughout most of the original X-Men saga stood Sir Ian McKellen's Erik Lehnsherr, better known to fans as Magneto. McKellen played the supervillain in all three films from the original trilogy before making a cameo in 2013's The Wolverine and playing a significant role in 2014's X-Men: Days of Future Past.
Classified as an Omega-level mutant, Magneto's abilities allow him to control anything metallic and create magnetic fields to use as weapons. Also notable is his staunch position supporting mutant rights (often mutant supremacy), although he has occasionally worked with the X-Men for the greater good through the years.
While Magneto's role in Doomsday is still a mystery, many expect him to be pitted right alongside Stewart's Charles Xavier as the mutants make their full debut in Earth-616. McKellen is also the oldest confirmed Doomsday star (as of writing), bringing a wealth of experience from more than two decades of experience with the Marvel universe.
Alan Cumming - Nightcrawler
Shocking many fans with a confirmed comeback for Avengers: Doomsday was Alan Cumming, who will reprise the fan-favorite mutant known as Nightcrawler. Also named Kurt Wagner, Cumming played this character only once in 2003's X2 before Kodi Smit-McPhee took on the role in 2016's X-Men: Apocalypse and 2019's Dark Phoenix.
Known for his kind-hearted nature and blue skin, Nightcrawler's most notable power is his ability to teleport, and he is highly agile and athletic. The hero can move at impressive speeds across any terrain, and his prehensile tail allows for extra movement while giving him another method of attacking foes.
While his role remains a mystery, Cumming recently teased a moment in Avengers: Doomsday with Pedro Pascal's Reed Richards in which they will come to blows with one another. Fans are eager to see him interact with countless other Marvel heroes as well, particularly with this being Cumming's first time in the universe in 23 years.
Rebecca Romijn - Mystique
The second new blue-skinned mutant making a debut in Avengers: Doomsday will be Raven Darkhölme/Mystique, played by Hollywood veteran Rebecca Romijn. She had a supporting role in all three original trilogy films and made a short cameo in 2011's X-Men: First Class, making it 15 years between Marvel appearances.
Depicted as both a hero and a villain, Mystique has made a name for herself with her shapeshifting abilities, allowing her to impersonate and replicate anybody she chooses. She is also a skilled fighter and has an enhanced healing factor, allowing her another advantage in battle against her enemies.
Known for her close relationships with both Professor X and Magneto, Mystique could realistically play both sides of the fence in the upcoming battle against Doctor Doom. The big mysteries here are which universe she comes from and how she will be influenced by her new supporting actors
Meanwhile, Romijn embodied the shapeshifting mutant Mystique in the original X-Men trilogy. She also made a cameo in 2011’s X-Men: First Class.
James Marsden - Cyclops
Often known as one of the X-Men's leaders, James Marsden's Cyclops is in line for a long-awaited return to the MCU in Avengers: Doomsday. He took on a leading role in all three original trilogy movies and had a cameo in X-Men: Days of Future Past, which gave him an 11-year gap between appearances for his iconic hero.
Also known as Scott Summers, Cyclops' power comes from the optic blasts that consistently shoot from his eyes without the assistance of goggles, which he can use to control how and when the blasts are fired. He can also absorb solar energy, and during his time in other media, he helps lead the mutants into battle.
At the very least, fans are hopeful to see Marsden finally suit up in the iconic blue and yellow suit Cylcops is best known for (similar to Wolverine's yellow suit from Deadpool & Wolverine). He should also play more of a central figure amongst the X-Men in Doomsday, giving him the opportunity for even more exciting storylines moving forward.
