It's possible Avengers: Infinity War and Avengers: Endgame set up Agatha Harkness' role in WandaVision. Marvel Studios' first TV series, WandaVision is an unusual superhero adventure crossed with a sitcom, with each episode inviting viewers to speculate as to what's really going on. We're now in the final stretch, which means WandaVision is beginning to reveal its mysteries.

WandaVision episode 7 finally confirmed long-standing theories, revealing Kathryn Hahn's mysterious character is in fact a dangerous sorceress named Agatha Harkness. This being WandaVision, the reveal was handled with a combination of magic and an inspired theme tune, confirming Agatha has been sabotaging Wanda's "Happily Ever After" since the moment she arrived in Westview. Agatha's motives are currently inscrutable, but they seem to be at least partly explained by her sense of humor, given the glee she seems to have taken in meddling with Wanda's sitcom world.

Related: How WandaVision Changes Agatha Harkness: Real Villain's Comics Origin

But that wasn't the only big reveal in WandaVision episode 7. Every episode features a commercial break that's full of deeper meaning, and the one in episode 7 finally hinted at just why Wanda and Agatha are both in Westview. The advert was for an antidepressant named Nexus, which "works to anchor you back to your reality - or the reality of your choice." Although some have theorized this means the MCU's Scarlet Witch is herself a "nexus being" - a term used occasionally in the comics and acknowledged by Elizabeth Olsen herself in interviews back in 2015 - this more likely refers to a phenomenon known as the Nexus of All Realities. But there's just one problem with that theory.

What Is The Nexus Of All Realities?

Erik Selvig Dark World Chalkboard

The Nexus of All Realities was actually name-dropped in Thor: The Dark World, in a scene in which the disturbed genius Erik Selvig presented a lecture on the nature of the Multiverse to stunned inmates of a psychiatric hospital. The scene is mostly remembered for its Stan Lee cameo - Selvig had borrowed his shoe as part of his presentation - but it actually subtly establishes the foundation of the MCU's multiverse. The chalk-board is littered with terms from actual theories of quantum mechanics, blended with comic book references to things like "the Fault" and "the Crossroads" - as well as the Nexus of All Realities.

In the comics, the Nexus of All Realities is found in the Florida Everglades. It's been described as a place where the fabric of spacetime itself is "exceedingly threadbare," and consequently sorcerers can use the Nexus to travel between the dimensions or boost their own power to remarkable levels. Presumably the MCU's version of the Nexus of All Realities is actually situated at Westview, which would explain why both Scarlet Witch and Agatha Harkness found themselves drawn to the same town; Wanda has used the power of the Nexus to create her sitcom-based reality and resurrect Vision, but the magic is only sustainable in close proximity to the Nexus, explaining why he can't leave the Hex. If this theory is correct, WandaVision will soon see Wanda and Agatha battle it out for control of the Nexus.

Where Is The Nexus' Guardian?

man-thing cover

There is, however, one problem with this theory; the fact the Nexus appears to be unguarded. In the comics, there are portals scattered across the universe that can be used to reach the Nexus, but every one of these is protected by a different "Nexus-Guardian" who has been appointed by an unknown force to prevent the power of the Nexus being abused. The most of these is the Man-Thing, who was alluded to in Thor: Ragnarok, but he's a far more appropriate guardian for a Nexus in the Florida Everglades than one beneath a town in New Jersey. Whether the Man-Thing is actually the appointed Guardian of Earth's Nexus of All Realities in the MCU or not, though, there should still be a Guardian.

Related: Spider-Man: Far From Home Hinted Fury Knew About WandaVision's Westview

The MCU timeline may well offer a clue as to the Guardian's fate. It is important to remember WandaVision is set just three weeks after Avengers: Endgame, which means the entire cosmos has just gone through a time of anarchy. Five years ago, Thanos the Mad Titan snapped his fingers, and instantly erased half the living creatures in the universe. It is entirely possible the Guardian of the Westview Nexus was one of the countless beings snapped out of existence, meaning for five years it went without a protector. Agatha Harkness could well have arrived in Westview during that five year period, claiming its power for her own. When the Guardian was restored by the Hulk's snap, it would have been too late; she could well have already mastered the Nexus, using it to defeat him in a similar manner seen in the comics in Quasar #50, where an enhanced sorceress almost killed the Man-Thing. And so when Wanda arrived in Westview, she didn't know the Nexus' power had already been claimed.

What Happened To The Nexus-Guardian?

WandaVision Bunny

If this theory is correct, what did Agatha Harkness do with the Nexus-Guardian? WandaVision may have already offered a clue, because she's frequently been shown with a pet rabbit - even bringing the bunny with her down into the basement for her fateful introduction to Wanda. While this may simply be (more) misdirection by Marvel, the bunny appears to be positioned as somehow important to the show. One possibility is that Agatha used her mastery of the Nexus' magic to transform the Nexus-Guardian themselves into a rabbit, one she has since enjoyed taking with her in order to taunt them by letting them bear witness to her actions. If this theory is correct, then Agatha's decision to get the bunny out for Wanda's twin boys to pet suddenly becomes rather sinister.

This may, however, mean Wanda can yet get some additional help in dealing with Agatha Harkness. Both witches appear to possess enough magical power to tap into the Nexus, meaning Wanda should be able to undo anything Agatha has done - including restore the Nexus-Guardian. Agatha's decision to keep the Nexus-Guardian alive, and to mock it by letting it see what she has been doing, could well prove to be her downfall in WandaVision.

More: Wandavision's Quicksilver Reveals Undo X-Men Canon Theory

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