The MCU’s Best Variant Was Introduced in Marvel’s Weirdest Show 5 Years Ago, Before Finally Arriving in Live-Action
Marvel Studios coined the term variant in the summer of 2021, when the Disney+ series Loki introduced the Time Variance Authority and its mandate to prune any timeline that strayed from the Sacred Timeline. In the Marvel Cinematic Universe, a variant is an alternate version of an established character from an alternate timeline, shaped by a single choice that modifies their history. The concept multiplied quickly across the Multiversal Saga, leading to crowd-pleasing appearances such as the Illuminati council in Doctor Strange in the Multiverse of Madness and the returning Spider-Man actors in Spider-Man: No Way Home. Outside cameos and fan service, though, the MCU rarely gave a variant a story of their own. Five years ago, one animated series promised to do exactly that, and its opening episode remains the best example of what the variant concept can accomplish.
Following the closure of Marvel Television and the mandate to turn Disney+ into an essential part of the MCU strategy, What If…? was Marvel Studios’ first animated show. The series premiered on August 11, 2021, and ran for three seasons before concluding on December 29, 2024. With Jeffrey Wright voicing Uatu the Watcher, the series proposed to use the Marvel Comics structure and make each episode focus on a specific moment in MCU history, where a change in the order of events led to unthinkable consequences. Across three seasons and 26 episodes, the series built out dozens of alternate realities, telling strange stories featuring variants of the MCU’s most popular faces. Still, the show’s premiere, “What If… Captain Carter Were the First Avenger?” remains its strongest instalment, in grand part due to the introduction of Captain Carter (voiced by Hayley Atwell).
Captain Carter Showed the Potential of the Variant Concept
The most compelling promise behind the variant concept is showing how a single decision, however small, can send an entire timeline down an unrecognizable path. Marvel’s first What If…? episode makes that case by remixing the familiar plot of Captain America: The First Avenger. In the original 2011 timeline, Peggy Carter stepped into a viewing booth while Dr. Abraham Erskine (Stanley Tucci) administered the Super Soldier Serum to Steve Rogers (Chris Evans). In What If…?, she chooses to stay in the room instead. Peggy’s decision leads a HYDRA agent to attack during the procedure. Steve is shot before the treatment can be completed, and Peggy steps forward to take the serum in his place. From there, the episode carefully tracks every consequence that follows. Steve becomes a support pilot who builds the HYDRA Stomper suit since he cannot fight hand-to-hand, while Peggy assumes the Captain mantle that would have belonged to him. The attentiveness to cause and effect separates the series premiere from much of what followed it in the anthology series. Few What If…? episodes bother tracing how a single change reshapes an entire world, preferring instead to just drop the audience into an alternate world whose rules are already established.
After establishing how compelling Captain Carter was as a standalone hero, the show pulls her into an ongoing arc, first pairing her with Nick Fury (voiced by Samuel L. Jackson) against a multiversal Ultron, then folding her into the Guardians of the Multiverse alongside Star-Lord T’Challa (voiced by Chadwick Boseman) and Killmonger’s Black Panther (voiced by Michael B. Jordan). By the second and third seasons, Captain Carter had become a recurring protagonist, hopping between dimensions to fight repeating threats. What If…? also revealed itself as a serialized story stretched across different backdrops, instead of a true anthology, with each subsequent season leaning harder into the concept. Because of that, audience enthusiasm cooled with each passing season. Despite that erosion, Captain Carter remains a fantastic variant that the MCU can still use.
Captain Carter Already Appeared in Live-Action, and She Can Do It Again
Captain Carter made her live-action debut in 2022’s Doctor Strange in the Multiverse of Madness, sitting on the Illuminati council of Earth-838 alongside variants of Professor X (Patrick Stewart) and Mister Fantastic (John Krasinski). That version of the character comes from Earth-838, a different timeline from the one in What If…?. We can tell by the character’s different story and her uniform changes, which means that, across the multiverse, multiple versions of Peggy Carter have taken the Super Soldier Serum in place of Steve Rogers. That version of Captain Carter dies in the movie, sliced apart by her own shield during a clash with the Scarlet Witch (Elizabeth Olsen). In the third season of What If…?, the first Captain Carter variant also sacrifices her life for the sake of the multiverse. Despite that, nothing prevents a third version of Captain Carter from appearing in the mainline MCU.
Marvel Studios confirmed Atwell’s return for Avengers: Doomsday during the 2026 San Diego Comic-Con panel, naming her character only as Peggy Carter. While she can appear only as part of Steve Rogers’ domestic life in the movie’s opening, Doomsday is a multiversal story confirmed to unfold in at least three separate timelines. That creates the opportunity for a costumed Captain Carter to stand among the heroes. Even if Doomsday keeps Atwell in a smaller role similar to her Avengers: Endgame appearance, Avengers: Secret Wars follows on December 17, 2027, and that film promises to pull from every corner of the multiverse. One live-action appearance and three animated seasons have already established Captain Carter as someone who should appear in a massive multiverse crossover.
What If…? remains available to stream in its entirety on Disney+, and Avengers: Doomsday arrives in theaters on December 18th.
