Agatha Harkness (Kathryn Hahn) was the first witch to recognize the full extent of Wanda Maximoff's (Elizabeth Olsen) true power. "This is chaos magic, Wanda! And that makes you ... the Scarlet Witch." Agatha declares in WandaVision.
Why was Agatha so afraid of the Scarlet Witch? Agatha also introduced the concept of chaos magic into the MCU, explaining that Wanda's ability to create something out of nothing was incredibly powerful, yet extremely dangerous when in the wrong hands.
Her fears were confirmed in Doctor Strange in the Multiverse of Madness when the Scarlet Witch effortlessly wiped out scores of powerful mages and heroes, her soul corrupted by the Darkhold. How did the Scarlet Witch get so powerful?
How did the Scarlet Witch get her powers in the Marvel comics?
The Scarlet Witch's powers in the Marvel comics originate from the evil Elder God Chthon. Per the Marvel Database, Chthon was one of the powerful Elder Gods that ruled the Earth millions of years ago. At one point in time, Chthon was banished from Earth. However, Chthon left his teachings and his chaos magic in the Darkhold and Wundagore Mountain, hopeful that one day he'd find a way to return.
He found an opportunity in baby Wanda Maximoff and a man called the High Evolutionary.
Wanda and her brother Pietro were kidnapped from their parents and taken to Wundagore Mountain. The High Evolutionary was determined to experiment on babies and imbue them with superhuman capabilities. As a result of the High Evolutionary's meddling, Wanda absorbed chaos magic.
Wanda's chaos magic granted her the ability to warp reality to her will as the Scarlet Witch. One of her most powerful comic book moments was when she wiped out most of the X-Men with three words. "No more mutants."
Did the Scarlet Witch get her powers the same way in the MCU?
Not in the slightest. When Agatha takes Wanda on a trip down memory lane in WandaVision Episode 8, she realizes that Wanda had magical abilities from the start. Wanda had always assumed it was luck that kept her and Pietro alive when they were trapped in the rubble next to a Stark bomb that never went off when they were kids.
Agatha explains that it wasn't luck that the bomb never went off. It was Wanda casting a probability hex without even realizing it.
Wanda's witchy mentor theorizes that Wanda's latent powers might've been snuffed out if she hadn't encountered the Mind Stone. Once again Wanda was being experimented on, but this time she had volunteered herself willingly. "We thought we were going to change the world," Wanda said sadly when Agatha questioned why she signed up to be a HYDRA experiment.
One day, HYDRA scientists led Wanda into a room with Loki's scepter, which housed the Mind Stone.
The Mind Stone revealed itself to Wanda, showing her a vision of the Scarlet Witch. Wanda didn't realize what the vision meant at the time, but the Mind Stone amplified her latent powers.
The Mind Stone also showed her what the future held, where Wanda was no longer a woman who just happened to have powers but rather the Scarlet Witch prophesied in the Darkhold. So Wanda had possessed powers since birth, but she had to accept her destiny in order to truly become the Scarlet Witch.
The fate of the Scarlet Witch after 'Doctor Strange in the Multiverse of Madness' is up in the air.
We've said it before and we'll say it again. We're certain that the Scarlet Witch did not die in Doctor Strange in the Multiverse of Madness. Not only is Wanda powerful enough to survive a mountain crashing on her, but she's also Earth 616's resident nexus being (well, in the comics anyway).
There can only be one nexus being per universe, so that gives Wanda extra powers in terms of altering reality as we know it.
Wanda's status as a nexus being means she possesses the ability to alter probable outcomes in her favor (like the Stark bomb never going off!). She may have destroyed all of the Darkholds across the multiverse, intending to sacrifice herself in the process, but if the Scarlet Witch had even the smallest desire to live, the odds are definitely in her favor.
There's simply far too much story left to tell with the Scarlet Witch to end at Wundagore Mountain. We'll see her again. The question is, when?