WandaVision finally has a confirmed villain in Agatha Harkness, but that doesn’t mean the show will not include Mephisto as fans have theorized from the beginning. With many questions still swirling about the creation of Westview, Wanda’s magic, and the impending fracturing of the multiverse, there are several openings for Marvel’s devil to make his debut. Agatha may not be the final villain to come out of Wanda’s break with reality.
The theory of Mephisto’s involvement comes directly from the comics, where he was responsible for driving Wanda into insanity. Scarlet Witch unknowingly used pieces of his soul to create her twins, and he killed Billy and Tommy when he reabsorbed them. Mephisto is linked to Agatha Harkness in this story because the witch removed Wanda’s memories of the twins after she lost them. However, the MCU is making many changes to the plotline from the comics already, so Mephisto’s connection could be very different in WandaVision.
In her theme song “Agatha All Along,” Agatha Harkness revealed she has been messing with Wanda behind the scenes. However, she does not seem to be the ultimate source of Westview’s problems, only an antagonist turning the situation in her favor. She walked into Wanda’s television world after it was already created, leaving a lot of blanks about Wanda’s situation.
Since WandaVision is setting up the Multiverse of Madness for the next Doctor Strange movie, it makes sense that there’s a bigger power than Agatha working behind the scenes. If Mephisto is still to come in WandaVision’s twisting story, there are multiple potential twists that could reveal the devil in the details.
Agatha Is In League With Mephisto
Since the MCU has turned Agatha Harkness into a full-scale villain instead of the more ambiguous position she occupied in the comics, she could be Mephisto’s ally in any nefarious plans he has for Wanda. Mephisto’s goal has always been to enslave human souls, which is an ideal villainous use for Wanda’s newfound reality-shaping powers.
Both Agatha and Mephisto might be planning to make use of Wanda being a Nexus Being, as the strange Nexus commercial hinted. Nexus Beings are keystones to the multiverse, and Scarlet Witch was a Nexus Being in the comics. If Mephisto has plans for multiverse, they are likely to revolve around Wanda, but Agatha needed to place herself in the neighborhood to keep a closer eye on the events of Westview, while Mephisto operates from the background or from his home pocket dimension of Hell.
Mephisto Is The Source Of Wanda’s Magic
Even Wanda does not seem to have all the answers about how her television world was created. She does not control Vision or her twins. She cannot bring people back from the dead, but mysteriously did this with Vision. It’s unlikely she has the ability to magically create two entire people like Billy and Tommy. As in the comics, Wanda may have been drawing on Mephisto’s power all along, which is why the twins vanished when Agatha’s plan was revealed. If she is a Nexus Being, she could be sourcing this magic that is more powerful than she has displayed before from a different dimension - or an extradimensional being like Mephisto.
The Break In The Multiverse Frees Mephisto
Everything is lining up in WandaVision to explain how the Multiverse of Madness will come to be. Wanda’s power over reality set the stage, and now as a Nexus Being, she would be a key to the stability of the multiverse. If anything happened to her, either from Agatha’s machinations or her own breakdown, she could cause the interdimensional chaos Doctor Strange will soon encounter. Whether or not Mephisto has a hand in Wanda’s troubles in Westview, the fracturing of the multiverse could bring Mephisto into play as the major villain of Phase 4.
Mephisto has never appeared in the MCU, despite the likes of Dormammu making it clear he'd fit in the universe. His powers and abilities will almost certainly differ from his comic counterpart, so he may not have a way to get to the MCU’s Earth right now, but all that could change by the end of WandaVision. If he is trapped in his Hell dimension or locked out of that Earth, the Multiverse of Madness Wanda is heading toward could release him upon the world.
Mephisto Is Still In The Town
Agatha isn’t necessarily the only villain in town. Even if he’s not working with Agnes, Mephisto may be maintaining his own presence in the neighborhood, acting on his own agenda. Not every Westview resident has been identified. Neighborhood queen bee Dottie remains suspiciously mysterious, indicating Dottie could be Mephisto in disguise, though there are other possible candidates for his Westview face up to and including Agnes’ pet rabbit Señor Scratchy. If Mephisto is working separately from Agnes, he’s hiding in plain sight, somewhere he can keep an eye on Wanda and act when he’s ready.
Mephisto Is Manipulating Events From S.W.O.R.D.
It’s possible Mephisto’s plan is not best served from inside Westview, but outside. If he’s maintaining a presence around Wanda, he could just as easily be hiding within S.W.O.R.D. His true goals may be better reached by controlling how the real world reacts to Wanda’s reality in Westview than controlling her reality itself. Agatha would be able to act as his agent inside if they are aligned, avoiding the need for his physical presence in the neighborhood. Instead, he manipulates S.W.O.R.D.’s response to ensure their interference does not change his intended outcome.
Though the many hints about Mephisto could be red herrings, Wanda’s show remains a perfect opportunity to introduce a major villain to cause problems through this phase of the MCU. There are only two episodes left to answer overflowing questions, but the show could still reveal Mephisto’s influence or leave it open as a tantalizing possibility for upcoming stories to confirm. WandaVision is primed to change the course of reality, and Mephisto can still be part of its incredible kickoff to Phase 4.