Marvel Studios shook the world at San Diego Comic-Con in 2024 when it announced Robert Downey Jr.'s return to the MCU not as Iron Man, but as the infamous Doctor Doom. This set up Avengers: Doomsday as the Multiverse Saga's ultimate showdown, with Doom posing a threat to all of reality. This necessitates pulling together heroes from across timelines to put a stop to the Latverian dictator's menace. Fans expect epic battles and chaos not just on Earth-616 but across other realities, especially since directors Anthony and Joe Russo return after helming Infinity War and Endgame. Avengers: Secret Wars, which also arrives in December 2027, promises an even bigger finale, drawing on comic book events in which heroes clash on Battleworld.
These films unite a massive ensemble, but only a select group earned official spots in both. The core cast was confirmed through live streams, interviews, and official announcements. Robert Downey Jr. leads the villain side, while Earth’s Mightiest Heroes and other powerful teams unite against him.
MCU Stars Featuring in Both Doomsday and Secret Wars
Robert Downey Jr. (Doctor Doom)
Arguably, the most surprising reveal in MCU history occurred when Robert Downey Jr. (RDJ) stood on the Hall H stage, unmasking not as Iron Man but as Victor von Doom. Marvel Studios President Kevin Feige confirmed that Downey will be the primary antagonist for both Doomsday and Secret Wars. RDJ is now the Thanos of the Multiverse Saga, albeit a bigger menace. He is expected to bring a complex, three-dimensional villainy to the screen, a role the Russos claim makes him the hero of his own story.
The transition from the MCU's greatest hero to its most formidable villain could prove to be one of the most amazing casting decisions of all time, depending on how well Downey embodies the role in the two-part finale. The actor has reportedly been working closely with the directors to develop a unique backstory for this version of Doom, ensuring he feels distinct.
Benedict Cumberbatch (Doctor Strange)
Benedict Cumberbatch is arguably the most competent foil to Doom, and his presence in both films is essential given his expertise in sorcery and multiversal shenanigans. Cumberbatch noted that Stephen Strange is central to the unfolding narrative, particularly in Secret Wars.
In the comics, Doctor Strange plays a pivotal role in the Secret Wars storyline as the Sheriff of Battleworld, a part that fans expect to see mirrored on screen. As the hero who has seen more of the multiverse than anyone else, Strange's expertise will be the Avengers' only hope amidst the collapsing realities.
Pedro Pascal (Reed Richards/Mr. Fantastic)
As the patriarch of the Fantastic Four, Pedro Pascal’s Reed Richards is essential to the conflict. The entire First Family will transition directly from The Fantastic Four: First Steps into Avengers: Doomsday. First Steps' post-credits scene even gave a hint of Doom's plans. Pascal brings a seasoned, high-intelligence energy to the role, positioning Reed as the primary scientific rival to Robert Downey Jr.'s Victor von Doom.
The dynamic between Reed and Doom is one of the most storied rivalries in comic book history. Pascal will likely lead the charge in Doomsday as the heroes attempt to stop the multiverse from unraveling. By Secret Wars, his role will evolve as he faces the consequences of Doom's rise to power, potentially serving as one of the few individuals capable of out-thinking the new dictator of Battleworld.
Vanessa Kirby (Sue Storm/Invisible Woman)
Vanessa Kirby's Sue Storm is an important character, serving as the emotional core of the Fantastic Four team. Beyond this, she's also one of the most powerful members of the team, as evidenced by their fight against Galactus in First Steps. Following her 1960s-set debut, Kirby is confirmed to bring Sue into the modern-day multiversal war. Her inclusion in both sequels ensures that the Fantastic Four remain the focal point of Phase 6, serving as the team that bridges the gap between different realities.
Joseph Quinn (Johnny Storm/Human Torch)
After finding global fame in Stranger Things, Joseph Quinn is already killing it in the MCU with his performance as Johnny Storm in Fantastic Four: First Steps. He's ready to bring his talents to both Doomsday and Secret Wars, and he expressed excitement when his participation was made official. His Human Torch will provide the much-needed energy and raw power the Avengers require in the multiversal crisis.
Quinn raved about working with Robert Downey Jnr and other stars, noting the scale of the production. Johnny Storm's journey will see him evolve from a young adventurer to a battle-hardened survivor across the two films.
Ebon Moss-Bachrach (Ben Grimm/The Thing)
Ebon Moss-Bachrach rounds out the First Family as the indestructible Ben Grimm. The actor has already been seen in early teasers for Doomsday, confirming that The Thing will be on the front lines from the beginning. Moss-Bachrach’s portrayal focuses on the tragic humanity behind the rock-hard exterior, a nuance that will be felt on screen as he loses his home universe.
The Thing's physical prowess will be tested like never before as he faces off against Doom’s forces. Moss-Bachrach is confirmed for both films, suggesting that Ben Grimm survives the initial collapse of reality to fight another day on Battleworld.
Anthony Mackie (Sam Wilson/Captain America)
Anthony Mackie's Sam Wilson is officially the man with the shield for the next generation of Avengers. Mackie's character will lead the Avengers in both Doomsday and Secret Wars, fulfilling the promise made at the end of Endgame. As the new Captain America, Sam Wilson will be the primary strategist trying to unite the scattered heroes against Doom’s overwhelming power.
Mackie told Deadline in early 2025 that he is the "Avenger from the old group that brings in the new group," signifying his role as the team's recruiter. Following the events of Brave New World, Sam will find himself at the center of an international and then interdimensional crisis. His leadership will be the glue that holds the team together when everything they know begins to fade away.
Florence Pugh (Yelena Belova)
Florence Pugh’s Yelena Belova transitioned from a supporting character to a lead pillar of the MCU. As the heart of the Thunderbolts team, Pugh is confirmed to carry her role into both Phase 6 Avengers films. Her dry wit and lethal combat skills make her the natural successor to Natasha Romanoff’s legacy within the franchise.
Yelena's involvement is particularly interesting as it brings the darker side of the MCU into the main spotlight. Pugh will lead her team of anti-heroes into a battle they are wholly unprepared for, forcing her to evolve into a true hero.
Sebastian Stan (Bucky Barnes)
The Winter Soldier is the ultimate survivor, and Sebastian Stan is officially back for his 11th and 12th MCU appearances. Stan will reprise his role as Bucky Barnes in both Doomsday and Secret Wars, serving as the Thunderbolts' tactical leader. Bucky’s experience as a Super Soldier will be vital as the heroes are outmatched by Doom’s technology and magic.
Simu Liu (Shang-Chi)
Despite the wait for his solo sequel, Simu Liu confirmed that Shang-Chi is a major player in the Avengers finale. Liu recently told People that he is "lucky enough to be a part" of both Doomsday and its successor, Secret Wars. The Ten Rings have long been rumoured to be an important McGuffin in the films. If this is the case, Shang-Chi's role is likely to be more significant than most.
Shang-Chi’s mastery of martial arts and his powerful artifacts make him one of the few heroes capable of standing toe-to-toe with Doom's elite forces. Liu has had a blast on set, developing friendships and even visiting Robert Downey Jr.'s special paradise on the Doomsday set. It'll be interesting to see the kind of impact he brings in his next MCU outing.
Letitia Wright (Shuri/Black Panther)
Letitia Wright confirmed that Shuri will return as the Black Panther for both upcoming films. As the leader of Wakanda, Shuri brings on board vibranium technology and the scientific genius necessary to combat Doctor Doom. Wright mentioned that Secret Wars is what's next on her filming schedule.
Shuri’s next adventure will be her biggest challenge yet. The latest teaser for Doomsday shows her home nation already reeling from the damage Doom is causing across the multiverse. She's even acknowledged that a "king has his duties to prepare our people for the afterlife."
Wyatt Russell (John Walker/US Agent)
The complicated John Walker is confirmed to return as part of the Thunderbolts crossover into the Avengers films. Wyatt Russell brings a volatile, unpredictable energy to the team, which will be tested as the multiverse begins to collapse. Walker’s desire to prove himself as a hero will likely lead him to take extreme risks in the fight against Doom.
While Walker may not have Sam Wilson's moral compass, his Super Soldier strength is an asset the Avengers cannot ignore. Russell is locked in for both films, indicating that John Walker will be a key part of the final stand in Secret Wars.
David Harbour (Red Guardian)
David Harbour’s Alexei Shostakov brings both muscle and heart to the ensemble. Confirmed to transition from Thunderbolts into the Avengers sequels, Red Guardian will finally get his wish of fighting alongside, or perhaps against, major global icons. Harbour’s performance provides the much-needed levity in what is expected to be a very dark story.
Beyond the comedy, Alexei is a powerhouse who will be essential in large-scale battle sequences. His paternal bond with Yelena Belova will likely be a key emotional anchor for both characters as they face the end of their reality.
Hannah John-Kamen (Ava Starr/Ghost)
Hannah John-Kamen returns as Ghost, a character whose unique molecular instability makes her a perfect fit for a multiversal war. Ghost will utilize her phasing abilities for stealth and reconnaissance. After a significant absence from the MCU following Ant-Man and the Wasp, Ava Starr recently rejoined the world stage as a member of the new team in the Thunderbolts*. The multiverse will benefit from her skillset again as she contributes to the war against Doom in the Avengers films.
Hayley Atwell (Captain Carter)
Hayley Atwell’s return to the MCU was solidified through a recent profile in The Hollywood Reporter. The report noted a massive deal for Atwell to reprise her role as Peggy Carter in both Avengers: Doomsday and Avengers: Secret Wars. This long-term commitment suggests that Atwell is finally moving beyond brief cameos to become a central pillar of the Multiverse Saga’s conclusion.
The emotional stakes for her return were teased in the first Avengers: Doomsday teaser. The footage shows Chris Evans' Steve Rogers returning to the 1950s-style home they shared at the end of Endgame. Steve is also seen holding a baby, which could be his child with Peggy, suggesting a possible significant role for the would-be mother.
Geraldo Amartey is a writer at The Direct. He joined the team in 2025, bringing with him four years of experience covering entertainment news, pop culture, and fan-favorite franchises for sites like YEN, Briefly and Tuko.
