What If...? pitches were rejected, and even some perfect multiverse opportunities have been missed, the series has been able to tell original and unique stories in animation that run parallel to the proper MCU. Audiences can anticipate a final season that goes even bigger and more impactful on the Multiverse Saga than anything that has been seen before.

Many eagerly await the What If...? season 3 release date, and it now makes sense to take a look at the many different characters that are slated to appear in the series. While many of the actors from the MCU have voiced their variants, some have not. Before the series begins, and a plethora of familiar Marvel characters grace the small screen, it is worth investigating the cast list for the show. Note that additional cast may be added throughout the run of the season, with other roles being set to be confirmed.

Hayley Atwell As Peggy Carter

Peggy First Appeared In Captain America: The First Avenger

British actor Hayley Atwell has been a major part of What If...? as Peggy Carter, and especially as Captain Carter, and will return in the new season. Stories surrounding Peggy becoming Captain Carter were embedded in seasons 1 and 2, and the character even crossed over to an ill-fated appearance in Doctor Strange in the Multiverse of Madness. With Hayley Atwell confirmed to return in Avengers: Doomsday, stories involving Captain Carter may become even more important in the universe.

While none of the revealed episode titles center around Captain Carter as they did in previous seasons, with "What If... Captain Carter Fought the Hydra Stomper?" as the most recent, Atwell may still play a prominent role here. With future plans for the character, necessary setup may be provided in the series. Atwell has been a part of the MCU since Captain America: The First Avenger, and her importance is unlikely to end soon.

Anthony Mackie As Captain America

Sam Wilson Last Appeared In The Falcon And The Winter Soldier

As shown in various clips released for the new season, Sam Wilson will be a part of What If...? season 3 and Anthony Mackie will return to voice him. The character has grown increasingly important to Marvel, and is set to receive his own film early next year with Captain America: Brave New World. In the meanwhile, Sam is set to gather alongside his Avengers team in the latest animated series.

Mackie has been set up for a larger role in the MCU since his first appearance in Captain America: The Winter Soldier. The Falcon played a large part in the group stories, but his role as Captain America, having taken the shield from Steve, appears to be even more important. It remains to be seen if the same origin will be provided to Sam in the animated series.

Sebastian Stan As Bucky Barnes

Bucky Last Appeared In The Falcon And The Winter Soldier

Bucky and his metal arm are set to appear in the latest season of What If...?, where Sebastian Stan will return to provide the voice of the popular character. Bucky has only grown more important in the MCU, with the actor also set to return in Thunderbolts*. The character was seen in the trailer for What If...?'s new season, where he appears to be in the 19th century.

Stan has grown as an actor through the years, and Bucky has become an increasingly interesting character. With a unique style and leading-man good looks, Stan has turned the complex character into a perennial favorite. Amidst a diverse body of increasingly interesting work, Stan shines in the MCU and is set to provide more layers to his character in the final season of What If...?.

David Harbour As Red Guardian

Red Guardian Last Appeared In Black Widow

David Harbour will return as Red Guardian in What If...? season 3. The actor played the character with humorous affection in Black Widow, and is set to have his role expanded in the Thunderbolts*. Before then, Harbour will bring his voice to the animated Marvel series, where he appears to be paired up with characters that include Bucky Barnes.

Harbour has become an in-demand actor after many years of working in the industry following his turn on Stranger Things. While the actor is a great , his humor and presence qualify him for larger and more interesting roles. Audiences have seen some of this in recent years, but it appears likely that the best for Harbour, and perhaps even for the Red Guardian, is still ahead.

Mark Ruffalo As Bruce Banner Aka The Hulk

Hulk Last Appeared In She-Hulk: Attorney At Law

Smart Hulk has persisted for too long, although that appears to end when Mark Ruffalo reprises the role in What If...? season 3. The character is set to appear in "What If... Hulk Fought The Mech Avengers?", an episode that is likely to show a rage-filled Hulk for the first time in years. As the Avengers appear set to transform with their giant series of mechs, a scary, threatening Hulk will fight against them.

Mark Ruffalo has become an important part of the MCU after he replaced Edward Norton for The Avengers. Ruffalo has an excellent, quiet charisma that contrasts well with the brutal terror of The Hulk. Audiences have been hoping for a feral Hulk to return to the franchise for some time, and it appears that this will finally happen in the latest season of What If...?.

Teyonah Parris As Monica Rambeau

Monica Appeared In WandaVision And The Marvels

Teyonah Paris will return as Monica Rambeau in the new season. The actor has become a prominent part of the universe after gaining powers in WandaVision from Wanda's hex. Her relationship with Captain Marvel was strained from Carol's disappearance, but cooperation grew between the heroes in The Marvels. That film closes with Monica being whisked off to another dimension, where she meets the X-Men's Beast.

What version of Monica will appear in this series remains to be seen. The character could connect with the stories told in the larger MCU, especially with the integration of X-Men in this show. However, that seems unlikely. Instead, the trailers show Monica working alongside Captain America to repel an invasion in the latest season of the Marvel series. The size of Monica's role remains to be revealed.

Kathryn Hahn As Agatha Harkness

Agatha Appeared In WandaVision And Agatha All Along

After an incredible run on the acclaimed Agatha All Along, Kathryn Hahn will return to What If...? as Agatha Harkness. After the Agatha showrunner recently confirmed that the villain is not reformed even in the larger MCU, it remains to be seen if Hahn will play a villainous role in the episodes. Agatha's story in the animated series is set for the episode "What If... Agatha Went to Hollywood?", with Hahn herself speaking about it back in September.

Agatha has become an increasingly important character in the MCU, with incredible powers that match the performer's electric charisma. After depth was provided to her backstory in Agatha All Along, the character could be explored further in the series, as many "what if" questions remain around Nicholas Scratch and her relationship to Death. Agatha is confirmed to appear in season 3 in a Hollywood episode that could cross over with characters like the confirmed Kingo, or the unconfirmed Trevor Slattery and Wonder Man.

Simu Liu As Shang-Chi

Shang-Chi Last Appeared In Shang-Chi And The Legend Of The Ten Rings

Shang-Chi has been poised to be a major character in the Marvel Cinematic Universe, but the hero has practically disappeared since his first film. Fortunately, Simu Liu will return as Shang-Chi in What If...?, where the character has been confirmed to appear in a western-themed episode. Liu will likely next appear in the Avengers films.

Liu has had an interesting career in Hollywood, having been launched into superstardom simply due to his MCU casting. The actor has great comedic chops, having spent the beginning of his career on a hit Canadian sitcom. He fits perfectly into the MCU, and there appear to be many plans for Shang-Chi to become increasingly important to the universe in the near future. Plans for a Shang-Chi sequel have been discussed, but official confirmation and updates are still awaited.

Hailee Steinfeld As Kate Bishop Hawkeye

Kate Bishop Appeared In Hawkeye And The Marvels

Hailee Steinfeld's Kate Bishop is set to appear in What If...? season 3, where recent photos have shown the character as a cowgirl alongside Shang-Chi. This is Steinfeld's first appearance in What If...?, although the actor is no stranger to animated fare. She has most recently provided the voice of Vi in the hit Netflix animated show Arcane. Steinfeld appears to be set for a significant future in the MCU with a large role among the Young Avengers.

Steinfeld's Hawkeye is one of the best new heroes to have come out of the franchise in recent years, and seeing her appear in this series is an exciting prospect. With musical, voice, and acting talent, Steinfeld has become one of the best young stars working today. The MCU seems to have plans for the actor's future, which may result in some of their best series and films yet.

Chris Hemsworth As Thor

Thor Last Appeared In Thor: Love And Thunder

One of the most important and long-running of the franchise, Chris Hemsworth will provide the voice of Thor in the latest season of What If...?. Thor has appeared several times in previous episodes of the series, and will recur in the final season. Hemsworth has played the character since Thor and has been a fixture of the Avengers movies since.

Hemsworth has become one of the most charismatic actors of today, with several successful projects outside of the MCU alongside his beloved performance as Thor. The actor most recently provided the voice for Orion Pax in Transformers One, and appears set to be a larger part of that franchise. He is next set to star in the untitled G.I. Joe/Transformers crossover film.

Tom Hiddleston As Loki

Loki Has Appeared In Various MCU Projects Beginning With Thor

After the end of Loki season 2, the character may have an unexpected kind of role in the season. Either way, Tom Hiddleston is confirmed to appear as Loki in What If...? season 3. The actor has been a Marvel mainstay for many years, being featured first as a villain before coming into a more heroic role. With Loki now acting as a temporal loom in the TVA, his role in the show may be important.

Tom Hiddleston has found great success as an actor through the years, but Loki is among some of his best work. After having auditioned for Thor, Hiddleston instead took on the complex character of Loki, which he imbued with creativity and moral flexibility. Having grown across various projects, it is exciting to wonder what version of the God of Mischief audiences will receive when the new season is released.

Additional Cast

Many New And Familiar Voices Will Return To The MCU Animated Series

Several other familiar faces from the MCU will return in the new series. Kumail Nanjiani, best known for his roles in Stuber and The Big Sick, will reprise his role as Kingo from Eternals. Kingo is an important part of the larger MCU, and several mentions of the character have been made in other series since his debut. Kingo's role in the season remains to be seen.

Dominique Thorne will also return to the series as Riri Williams aka Ironheart. The actor has a titular series in the works that will be released in 2025. Thorne has built a name for herself around her appearance in Black Panther: Wakanda Forever with impactful roles in Judas and the Black Messiah and If Beale Street Could Talk. Her character is set to be an important part of the MCU moving forward.

In addition to all of these, Devery Jacobs will return as Kahhori. Kahhori was a new Marvel hero created for the Disney+ series who first appeared in season 2. Devery Jacbos is perhaps best known for her work on the FX series Reservation Dogs, but she has also appeared in other various programs. Highlights of her career include roles in Backspot and The Order. She has also appeared as Bonnie in the MCU series Echo.

Josh Brolin has been confirmed to recur as Thanos in the series. Thanos has appeared in a few episodes of the series through the years, but it is always exciting to see Brolin return in the iconic villain role. Brolin has been busy with the Dune films and Brothers. The actor is perhaps best known outside of his MCU work for playing Cable in Deadpool 2 and starring in the Academy Award-winning No Country For Old Men.

Alison Sealy-Smith will appear in the series as Storm, one of the major X-Men characters. Sealy-Smith has played the role for many years, having voiced Storm in the animated X-Men: The Animated Series as well as in its recent revival, X-Men '97. Storm appears in the trailers for the series, where she appears to take on Thor's incredible powers and become the god of thunder.

More roles will be expanded in the series, with Oscar Isaac, star of Moon Knight, set to play a role in the final season. In addition, Seth Green will return to provide the voice of Howard the Duck, where the character will receive a full episode entitled "What If... Howard the Duck Got Hitched?"

Cast from Guardians of the Galaxy are also set to return, with Michael Rooker reprising the role of Yondu and Karen Gillan appearing as Nebula. Tessa Thompson's Valkyrie will return in the series, as well as Dominic Cooper as Howard Stark and James D'Arcy in the role of Jarvis. Walton Goggins, who previously played Sonny Burch, is set to appear, as well as Meng'er Zhang, Taika Waititi, Kat Dennings, and Laurence Fishburne, who previously played Bill Foster in Ant-Man & the Wasp.

Several performers who played important roles to S.H.I.E.L.D. and the larger authorities in the universe are set to return as well. Wyatt Russell, who will next star in Thunderbolts*, will appear as John Walker. In addition to this, Clark Gregg, who played Agent Coulson, and Emily VanCamp, who played Sharon Carter in the Captain America films, have been confirmed as part of the voice cast. Just as important, Samuel L. Jackson will appear in the series as Nick Fury.

Ross Marquand will also be returning to the series, potentially providing voices for several familiar characters. After taking over the roles of Red Skull and Ultron in various Marvel projects, including Doctor Strange in the Multiverse of Madness and Avengers: Infinity War, the actor could be reprising those roles here, although this is not confirmed. He could also be providing the voices for Professor X and Apocalypse. In addition, Marquand has voiced Doctor Doom in the past, and could do so again here.

Several additional performers have been added to the cast in smaller roles. Gene Farber will be voicing Vasily Karpov, Tom Vaughn-Lawlor will reprise his role as Ebony Maw, and David Kaye of Eternals will return as Arishem the Judge. Rachel House, who played Topaz, and Hamish Parkinson, voice of Beerbot 5000, a role that the actor played in Thor: Ragnarok, will appear.

Other guest stars have been confirmed by ComicBookMovie.com, including America Ferrera, Jason Isaacs, Natasha Lyonne, Allen Deng, DC Douglas, and Darin De Paul. Lyonne is confirmed to be playing a character named Byrdie, while the rest of the cast still await confirmation on their roles. With this in mind, and with so many performers attached, it seems clear that the final season of What If...? will be the biggest yet, with plenty to offer casual and dedicated MCU fans alike.

MCU Movies

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  Captain America: Brave New World

  Release Date

  February 14, 2025

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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

  December 17, 2027

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