10 Most Powerful MCU Characters Introduced In What If…?

Warning: This article contains spoilers for What If...? season 3.

Marvel Studios has introduced some of the most powerful characters in the history of the MCU in the animated What If...? series. Spanning three seasons between 2021 and 2024, Marvel Animation's What If...? explored some wild and wonderful alternate universes across the MCU's multiverse, and introduced a plethora of interesting, exciting and outlandish variants of some of Marvel's most iconic characters. What If...?'s expansive concept created the opportunity for some incredibly powerful and wide-reaching characters to appear, where live-action may not have done them justice.

Among some of the most memorable variants introduced to the MCU in What If...?'s three seasons were T'Challa's Star-Lord, Happy Hogan's Freak, the Mech Avengers and Xu Xialing's Hood. However, there are many more variants in What If...? who have demonstrated abilities that cement them as some of the most formidable and unmatched characters in the entire MCU. This makes these What If...? characters' possible move to live-action all the more exciting, especially since many of their live-action counterparts have already been established in the MCU.

10 Byrdie

Byrdie Debuted In What If...? Season 3, Episode 4, "What If... Howard The Duck Got Hitched?"

Before she makes her live-action MCU debut in 2025's upcoming The Fantastic Four: First Steps, Natasha Lyonne joined What If...?'s final season to voice Byrdie, the hybrid daughter of Darcy Lewis and Howard the Duck. Byrdie's powers first began to present themselves when she was still in egg form in What If...? season 3, episode 4, where she emitted a huge amount of energy to take down the villainous armies battling for her possession. Byrdie returned as an adult alongside Captain Carter, Kahhori and Storm in What If...? season 3's double-finale, and became even more powerful.

In her adventures as an adult, Byrdie showed off her flying skills and her technical knowledge, but received her greatest enhancement at the hands of the Watcher. After taking the Watcher's oath, Byrdie received his extra-dimensional abilities, which enhanced her natural human/duck hybrid powers. It's unclear whether Natasha Lyonne will be playing Byrdie in The Fantastic Four: First Steps, or a new MCU character, but Byrdie's possible live-action debut in another upcoming MCU project is very exciting after What If...? season 3.

9 Mega-Hulk

Mega-Hulk Debuted In What If...? Season 3, Episode 1, "What If... The Hulk Fought The Mech Avengers?"

Bruce Banner is already one of the strongest characters in the MCU, but What If...? season 3's premiere gave him an incredible power upgrade. "What If... the Hulk Fought the Mech Avengers?" saw Banner enhance his gamma radiation-based abilities with a gamma bomb, which grew him immensely in size, allowing him to take on the army of Hulk monsters that he previously unleashed on the world. A combination of the Hulk and Godzilla, the Mega-Hulk marked a dramatic and terrifying shift for Bruce Banner.

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Even as the Mega-Hulk, Bruce Banner managed to retain a semblance of his humanity, as his friendship with Sam Wilson allowed his rampage to be assuaged and the world to be saved. This could have paved the way for Marvel Studios to finally explore a live-action adaptation of 2007's World War Hulk event, or any other notably Hulk-centric storyline from Marvel Comics. Mark Ruffalo's Bruce Banner has been severely underused in the MCU in recent years, so it's great to see this supremely powerful Hulk debut in the MCU.

8 Kahhori

Kahhori Debuted In What If...? Season 2, Episode 6, "What If... Kahhori Reshaped The World?"

Kahhori was introduced in What If...? season 2 as an original character created for the animated series, with no counterpart in Marvel Comics or currently in the live-action MCU. A member of the Mohawk Nation, Kahhori received her incredible gifts after being exposed to the energy of the Tesseract, which fell onto pre-colonial America in Kahhori's reality. She quickly harnessed her new powers and became the most formidable member of her new tribe, and used these gifts to aid Captain Carter in the fight against Doctor Strange and form a team alongside Captain Carter, Byrdie and Storm.

What If...? season 3's double-finale saw Kahhori empowered with the abilities of the Watchers after taking Uatu's oath. This enhanced her Tesseract-fueled powers, which include superhuman strength, speed, agility, healing, energy projection and telekinesis, among others. There have been calls for Kahhori to debut in live-action ever since her appearance in What If...? season 2, and the ending of What If...? season 3 may have made this transition even more likely for the new cosmic superhero.

7 Doctor Strange Supreme

Doctor Strange Supreme Debuted In What If...? Season 1, Episode 4, "What If... Doctor Strange Lost His Heart Instead Of His Hands?"

What If...? season 1, episode 4 explored a universe in which Doctor Stephen Strange tried to break the Absolute Point of Christine Palmer's demise. His attempts to harness enough power to break this Absolute Point transformed him into a monstrous amalgamation of various haunting creatures, twisting his body and his mind, and his breaking of an Absolute Point led to the destruction of his entire reality. Strange Supreme returned as a Guardian of the Multiverse before setting out to try and restart his own universe.

Strange Supreme became an outright villain in What If...? season 2, but a moment of clarity saw him sacrifice himself and use his own soul to restart his destroyed reality. This universe was revisited in What If...? season 3's finale, which revealed that, there, Strange Supreme has absolute power. Despite his death, Strange Supreme is still seen as one of the most powerful and influential characters in the entire multiverse, with the power to void even the Watchers' abilities, so the possibilities for Benedict Cumberbatch's live-action Doctor Strange have just expanded.

6 Riri Williams’ Vision

Riri Williams' Vision Debuted In What If...? Season 3, Episode 5, "What If... The Emergence Destroyed The Earth?"

Before she returns to live-action in 2025's upcoming Ironheart series, Dominique Thorne reprised her Black Panther: Wakanda Forever role of Riri Williams in What If...? season 3. Williams was featured as the central hero operating on the fragments of an Earth ravaged by the emergence of the Celestial Tiamut and a war won by a nanite-enhanced Mysterio. Mysterio used his new technological powers to control the Vision, but Riri Williams still brought the synthezoid down and used his equipment to enhance herself into a human/synthezoid hybrid.

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This evolution made Riri Williams one of the most powerful characters in the MCU, as she harbored the powers of the Vision, which are almost incomprehensible. This upgrade allowed Williams to see through Mysterio's illusions and eventually defeat the original Spider-Man villain, with the help of the Watcher, bringing hope back to the broken world of What If...? season 3, episode 5. Riri Williams is set to return to live-action in 2025, and White Vision will follow in 2026, so it's possible this Ironheart and Vision crossover could soon return to the MCU.

5 Zombie Scarlet Witch

Zombie Scarlet Witch Debuted In What If...? Season 1, Episode 5, "What If... Zombies?!"

Elizabeth Olsen's Scarlet Witch is already one of the most powerful and unmatched characters in the MCU, which makes the introduction of even more dangerous variants such as What If...?'s zombified Scarlet Witch even more terrifying. Season 1's "What If... Zombies?!" debuted this haunting villain, who fell victim to the Quantum Virus and was transformed into a zombie, but retained her Chaos Magic abilities like other zombified characters. Zombie Scarlet Witch seems completely unbeatable, which is expected to form the story for the MCU's upcoming Marvel Zombies series.

In the MCU, Wanda Maximoff's Scarlet Witch is not only a witch, but her Mind Stone enhancements grant her the ability to shape reality at will. She put this to the test in WandaVision by establishing the Hex around Westview, New Jersey, and playing sitcom-style scenarios inside, and became a bona fide villain in Doctor Strange in the Multiverse of Madness. While many wait for the Scarlet Witch to return to live-action, the upcoming return of the zombified Wanda will sate viewers' appetites, and she could prove even more powerful than her live-action counterpart.

4 Celestial Agatha Harkness

Celestial Agatha Harkness Debuted In What If...? Season 3, Episode 2, "What If... Agatha Went To Hollywood?"

What If...? season 3's second episode was the first of the animated series to feature Kathryn Hahn's original Salem witch, Agatha Harkness. This story imagined Agatha traveling to Hollywood to gain enough energy from the Eternals to make her capable of absorbing the Celestial Tiamut's power and thwarting his emergence. After teaming up with Kumail Nanjiani's Kingo, she was successful, allowing her to become a Celestial-like being herself, which marked a significant upgrade for the popular and beloved MCU witch.

With the power of the Celestial Tiamut and all the Eternals at her disposal, Agatha Harkness cemented herself as perhaps the most formidable character in her home reality. She uses these powers to defeat the Celestial Arishem, but then makes the courageous decision to relinquish her new abilities and become a true movie star alongside Kingo. Of course, this won't stop a Celestial Agatha Harkness from possibly appearing in the live-action MCU, which would be a fantastic way to follow on from 2021's Eternals and 2024's Agatha All Along, neither of which have confirmed sequels.

3 Infinity Stones Captain Carter

Infinity Stones Captain Carter Debuted In What If...? Season 2, Episode 9, "What If... Strange Supreme Intervened?"

Even though this choice by Marvel Studios received some criticism, Hayley Atwell's Captain Carter becoming one of the most consistent character in What If...? allowed the entire series to have a clear throughline. Peggy Carter became a super soldier instead of Steve Rogers in the universe explored in What If...?'s first ever episode, and she gained more and more power with each new adventure she embarked on. This ultimately led to her harnessing the power of the Infinity Stones in What If...? season 2's finale, which forged her into one of the MCU's most powerful figures.

By the time she returned in What If...? season 3, episode 7, "What If... the Watcher Disappeared?," Captain Carter had relinquished the Infinity Stones. Even so, she soon received another significant upgrade by taking the Watchers' oath, leading to her epic and poignant sacrifice to save her friends. Hayley Atwell has already portrayed a Captain Carter variant in live-action, and it would be fantastic to see her bring a new iteration to life, perhaps in 2026's Avengers: Doomsday following confirmation of her casting in the Phase 6 crossover movie.

2 Infinity Ultron

Infinity Ultron Debuted In What If...? Season 1, Episode 7, "What If... Thor Were An Only Child?"

While the Infinity Stones managed to transform Captain Carter into an even more powerful hero than she ever imagined, the Stones also helped one of Marvel's most iconic supervillains to become a menace to the entire multiverse. In his home universe, Ultron successfully uploaded his consciousness into the Vision's body, and claimed the Infinity Stones from Thanos. This gave him the power necessary to destroy his entire universe and, after hearing the Watcher in the Observational Plane, waged war on the multiverse, only being defeated by the combined might of the Guardians of the Multiverse.

James Spader was recently confirmed to be reprising the role of Ultron in the MCU's upcoming Vision series, but an animated variant of Infinity Ultron came back before him. What If...? season 3's Ultron never heard the Watcher in the Observational Plane, so remained alone in his empty universe for eons, and this loneliness convinced him to help Captain Carter and her team when the Watcher found himself in trouble. Ultron absorbed a shard of the Observational Plane, finding himself able to access the Fifth Dimension, but even this didn't make him strong enough to stop the Watchers.

1 Uatu The Watcher (& His Team)

The Watcher Debuted In What If...? Season 1, Episode 1, "What If... Captain Carter Were The First Avenger?"

While any number of these What If...? characters could compete for the title of Most Powerful, few have come close to the power harbored by Uatu the Watcher. Jeffrey Wright voices this all-powerful and omniscient cosmic being in every episode of What If...?, narrating the stories from across the multiverse that he watches from his post on the Observational Plane in the Fifth Dimension. The Watchers are a supremely powerful race with almost unmatched powers, but What If...? season 3 saw several heroes receive the Watchers' incredible and coveted gifts.

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The Watcher gifted his superior abilities to Captain Carter, Kahhori, Storm and Byrdie in What If...? season 3's finale, allowing them to harness the power of the Watchers while still exhibiting their own natural powers, too. This debuted the most powerful superhero team in the MCU, which makes the prospect of them making the move into live-action very exciting. If the Watcher joins this team permanently after What If...? season 3, audiences might finally get to see the Watcher in action in the MCU proper, changing the power rankings of the franchise forever.

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What If… ? is an animated anthology series set in the Marvel Cinematic Universe which features fan-favorite characters, including Peggy Carter, T’Challa, Doctor Strange, Killmonger, Thor, and more. The new series, directed by Bryan Andrews with AC Bradley as head writer, features signature MCU action with a curious twist. The show sees Uatu the Watcher, an omnipotent being that observes the events of multiple universes from afar as they unfold, unable to interfere. However, things shift when an entity peers beyond the veil, jeopardizing the multiverse. 

Release Date August 11, 2021

Finale Year December 22, 2024

Cast Samuel L. Jackson , Stanley Tucci , Michael Douglas , Sean Gunn , Mark Ruffalo , Karen Gillan , Tom Hiddleston , Jeffrey Wright , Michael B. Jordan , Toby Jones , Sebastian Stan , Paul Rudd , David Dastmalchian , Natalie Portman , Josh Brolin , Dominic Cooper , Jeff Goldblum , Hayley Atwell , Djimon Hounsou , Chadwick Boseman , Taika Waititi , Chris Hemsworth , Neil McDonaugh , Jeremy Renner , Michael Rooker

Seasons 3

Writers Ashley Bradley , Matthew Chauncey

Directors Bryan Andrews

Showrunner Ashley Bradley

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