WARNING: Minor spoilers follow for WandaVision Episode 7, "Breaking the Fourth Wall," now streaming on Disney+.
The latest episode of WandaVision, "Breaking the Fourth Wall," finally revealed Agnes, the nosy neighbor, is actually the evil witch, Agatha Harkness. Agatha has been manipulating events ever since the beginning of the series, posing as Wanda and Vision's neighbor and Wanda's friend. While it was long ago theorized that the character was the villain of the series, the revelation still came as a surprise. And better yet, it leads to a massive mystery of its own.
With Agatha finally unveiled as WandaVision's main antagonist, let's look at all of the possible reasons she has to be in Westview.
Agatha Wants the Secrets of Westview
Since the premiere episode of WandaVision, fans have seen that Wanda has control over the people of Westview and the reality she has altered. She has rewritten the people's personalities, changed decors and even manipulated the size of her Hex. However, for reasons that remain unknown for the time being, Agatha isn't affected by Wanda's power. While everyone is under Wanda's control to a certain degree, Agatha is completely independent.
But despite that, it appears she doesn't understand how Wanda is pulling this all of. After all, the "recast" Pietro was sent to pry information out of Wanda and try to learn how she was able to create her alternate reality and control all of it. Agatha may not be affected by Wanda's control, but she may want to unlock her secrets to get that power for herself.
Agatha Wants the Twins
When revisiting the first episodes of WandaVision with the information that Agnes was the villain all along, it does appear like she has a singular goal. In the second episode of the series, she's already talking to Wanda about having kids, and when the twins are finally born, she expresses a quick interest in them. She even shows up at the house uninvited to help calm the babies, something she is able to do after spraying the two kids with perfume. Only it may not be perfume, given that the kids inexplicably grow up on their own moments later.
Agatha has a clear interest in the twins, given that she also manipulated events by killing their dog Sparky, likely in an attempt to have them grow up yet again. Now, in "Breaking the Fourth Wall," Agatha brings the two kids home, and they have since disappeared. It's possible she has been working to divide Vision and Wanda in order to take their children. What she wants with them is unclear, but it's possible she may need them to perform a special ritual -- one that could awaken a bigger evil.
Agatha Wants Revenge on Wanda
In "Breaking the Fourth Wall," the episode flashes back to previous scenes from WandaVision to show fans how Agatha was behind everything. One of those scenes showed that it was Agatha herself who was "interviewing" Wanda during her Modern Family-inspired talking head. At the time, the interviewer asked Wanda if she felt like what was happening to her was something she deserved. In the context of the episode, the question made sense, but knowing that it was Agatha asking, it could be perceived as an accusation of sorts.
Wanda may be an Avenger, but some people on the outside may see her as a villain. After all, she started off as an ally of Ultron, before the villain tried to wipe out life across the planet. Moreover, at the start of Captain America: Civil War, Wanda accidentally caused the death of multiple people in a building during a mission in Lagos -- an accident that was referenced in the in-world commercial of "On a Very Special Episode..." If Wanda caused the death of someone Agatha loved, she could be looking for revenge.
Agatha Needs Wanda's Powers
At the end of "Breaking the Fourth Wall," Wanda descends into Agatha's basement where she discovers the evil witch possesses a magical book which appears to be the Darkhold, an artifact whose power could easily be connected to the upcoming film Doctor Strange in the Multiverse of Madness. It's possible that Agatha needs Wanda's reality-altering powers to access the wider multiverse, as part of her villainous, overarching plan.
The Darkhold has magical origins, being created by the sinister god Chthon, and it's the gateway to many magical dangers. If the full secrets of the book are unlocked, its power could create the chaos at the center of the Doctor Strange sequel and maybe even the untitled Spider-Man 3. The multiverse has a large role in events to come in the Marvel Cinematic Universe, and it could all start with Agatha.
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+.