The first season of What If…? introduced arguably the most powerful villain in the MCU to date. Namely, Infinity Ultron. This variant of the corrupt A.I. used the Infinity Stones to not just halve the universe’s population like Thanos but also embark on a bid to conquer the entirety of reality. It took the assembled Guardians of the Multiverse — plus, Zola, of all people — to stop him.
But if a single character were to beat Infinity Ultron all on their lonesome, who would that be? The r/MarvelStudios subreddit community has been debating this thorny question after it was pitched by u/lukeaslim. Clearly, no one in the franchise at the moment could do it, so the Marvel fans delved into the comics to come up with someone strong enough to take on Infinity Ultron single-handedly.
One fan came up with three god-tier characters who might be up to the task. The Beyonder, Mr. Fantastic and the Invisible Woman’s kid, Franklin Richards, and The One Above All — basically the god of the Marvel universe.
Professor X’s son Legion could be in with a shot, too.
Not to mention The Living Tribunal, who appeared in a brief cameo in Doctor Strange in the Multiverse of Madness.
The best answer, though, has to go to the commenter who must’ve woken up this morning with murder on his mind.
It’s Ultroning Time.
While Infinity Ultron’s character appears to be done with, so we probably won’t see him return in What If…? season two, some of these other entities mentioned in this thread could show up in the MCU soon. Reed Richards alluded to his son Franklin — who has vast reality-warping powers — in Doctor Strange 2 while The Beyonder is the villain of the Secret Wars comics event. Infinity Ultron could look like small fry in comparison to the big-hitters who are coming in Phases Five and Six.