WARNING: The following contains spoilers for WandaVision Episode 8, "Previously On," streaming now on Disney+.
When looking at the mystical characters in Marvel Comics, it is easy to think that Doctor Strange is the most powerful magic practitioner of them all. He is called the Sorcerer Supreme, after all. However, that might not be true, and in the Marvel Cinematic Universe, WandaVision might have proven that there is one witch that is more powerful than even Stephen Strange. At the end of Episode 8, Agatha Harkness named Wanda the Scarlet Witch, a being who possesses the most powerful form of magic — Chaos Magic.
Chaos Magic was considered a myth, and in the comics, not even Doctor Strange believed it existed. However, this is what Wanda possesses. She is not a mutant, rather, her magic power allows Wanda to change reality to anything she wishes, with her only limit being her imagination. In the comics, she did this in House of M, and in WandaVision, she did it to an entire town. Now, she seems to be getting even stronger.
Agatha Harkness is a powerful witch who has been around for hundreds of years. As a young witch, she defeated her entire coven as they all teamed up to attack her. She has tapped into the dark arts, and she made it clear to Wanda that she has practiced her magic for eons. Wanda, on the other hand, knows nothing about how her magic works. She doesn't know her limitations, and Harkness showed that Wanda doesn't have many. With no training, little experience and complete ignorance of what she really is, Wanda showed great power without any training whatsoever.
This makes her more powerful than Doctor Strange, but it does not make her a more powerful magical practitioner than the Sorcerer Supreme. The Avengers and Earth's mightiest heroes showed that Thanos was more powerful than all of them, but that did not mean he was unbeatable. Even as strong as Thanos was, there was still a 1-in-14,000,605 chance that the heroes could beat him. What it took were the heroes to choose the right tactic to take down the Mad Titan. That was all because of Doctor Strange, who knew when and how to beat Thanos. This wisdom is what makes Stephen Strange the Sorcerer Supreme.
In the comics, Doctor Strange is always there to stop Wanda when needed, and, more recently, has cleaned up some of her messes. In "Avengers Disassembled," the Scarlet Witch destroyed the entire team and even killed Agatha Harkness. Doctor Strange arrived and shut her down in Avengers #503 by Brian Michael Bendis, David Finch, Olivier Coipel, Danny Miki, Frank D'Armata, Richard Starkings & Albert Deschesne. In the recent Empyre storyline by Al Ewing, Dan Slott and Valerio Schiti, she was powerful enough to bring mutants back from the dead, but Strange had to help her send them back when they returned as zombies.
The Scarlet Witch will appear in Doctor Strange in the Multiverse of Madness. There is a good chance they will either need to work together or that Strange will need to fix something that she does wrong. Either way, it shows that Wanda Maximoff might be the most powerful magic-user in the MCU, even more so than Doctor Strange.
Written by Jac Schaeffer and directed by Matt Shakman, WandaVision stars Elizabeth Olsen as Wanda Maximoff/Scarlet Witch, Paul Bettany as Vision, Randall Park as Agent Jimmy Woo, Kat Dennings as Darcy Lewis, Teyonah Parris as Monica Rambeau and Kathryn Hahn as Agnes. New episodes air Fridays on Disney+.