Agatha Harkness' backstory and origin was revealed in WandaVision episode 8, and it explains why Mephisto was never needed as the show's villain. Given its mystery box nature, WandaVision has inspired almost countless different fan theories over who and what was really going on in Westview. One of the most compelling - and persistent - is that WandaVision's villain was Mephisto, with various clues, hints, and Easter eggs apparently alluding to the devil of Marvel Comics.

Barring a last-minute twist, Mephisto is not WandaVision's villain, even in a capacity of being the one to pull the strings behind Agatha. With a lot of story to wrap up in the finale, then it seems highly unlikely Mephisto will be unveiled, which means talk of the devil being in the details was little more than a red herring. While that may be disappointing to any viewers hoping for the character's arrival, the events of WandaVision make it clear that there's no need for him.

Related: Why Agatha Wants Scarlet Witch's Power

WandaVision episode 8 showed off Agatha's origin, with her taking powers from other witches in her coven during the Salem Witch Trials. This cements that Agatha is indeed an incredibly old and powerful being in her own right, and while it isn't fully clear exactly what Agatha wants to achieve with Scarlet Witch's power, there is an obvious motivation there: Agatha has spent centuries honing her craft, learning spells and incantations to become more powerful, and it comes naturally to Wanda. With her own very high power level and an intriguing origin story, then it makes her a fully-rounded villain, so there's no room for someone else above her.

Agatha Harkness surrounded by the witch's coven in WandaVision

Indeed, introducing Mephisto wouldn't do much but undercut and devalue WandaVision's Agatha twist. She's strong enough and compelling enough to be a great villain in her own right, backed by Kathryn Hahn's stellar performance. This is further aided by the fact that Agatha has been around on the show all along, so while it was a twist, there's more overt setup for it than introducing Mephisto. Agnes/Agatha feels grounded in what the show was doing, and now it's fleshed the character out more, it further adds to her appeal. Her backstory is very specific and fits with the story, because it makes it more centered around the idea of witches and magic, directly linking itself to the reveal of Wanda as the Scarlet Witch, which isn't something that would've been achieved with Mephisto.

Of course, just because there isn't room for Mephisto in WandaVision, that doesn't rule him out of the MCU's future movies and shows. The trailer for Loki hinted at Mephisto too, and he'd certainly be a major new threat for any of the Marvel heroes to have to contend with in Phase 4 and beyond, so it seems likely the character will be introduced eventually. For WandaVision, though, while the theories did make sense for a time, choosing Agatha Harkness as the main villain was a better choice to serve its narrative and set up not only an exciting endgame, but connecting to Scarlet Witch's future and powers as well.

Next: WandaVision's White Vision: Episode 8 Post-Credits Scene Explained

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