Hello guys. I would like to share my theory here about "WandaVision" that in reality the Nightmare would be the main villain behind the events of the series. So here we go:

Making a quick introduction, Nightmare is one of Doctor Strange's main villains in the comics. He is the ruler of the Dream Dimension, a dimension in which tormented people end up having access to it, and to which the Nightmare takes advantage of it to carry out its evil plans. Well, among his abilities, he has the power to extract psychic energies from the subconscious minds of dreamers.

In "WandaVision", which takes place right after "Avengers: Endgame", Wanda is plagued by the loss of Vision. With that, when sleeping, she would end up in that dimension. As I said, having this power to extract psychic energies from people, the Nightmare would see the enormous potential that it has in Wanda, after all, her powers are totally related to psychic energies, since they come from the Mind Stone.

The series is still in episode four and is already blaming everything that it would just be Wanda's own fault, which would be a great way to trick viewers. Wanda, in reality, is being manipulated / controlled by the Nightmare. But what would be his plan? Simple, the Nightmare is a being that can only appear in people's dreams, he cannot physically appear on the Earth Plane. With that, he would try to get around this through Wanda (by the way, that’s why he doesn’t appear, as he doesn’t yet manages to leave its dimension).

In the most recent episode, we found that the city of Eastview disappeared from the map and Westview appeared in its place. The city of Eastview would actually have been swallowed up by the Dream Dimension and Westview appeared as a perfect life dream for Wanda, with her married to a still alive Vision, having children with him, in short, a perfect life like American sitcoms. However, we can see remnants of the villain through the commercials, which in showing in disguise the traumas of Wanda, reveal his worst nightmares.

At the end of the series, somehow, the Nightmare ends up, at least in parts, winning, which would lead to the events of "Doctor Strange in the Multiverse of Madness", which as we know, will connect to the series and is being sold as a horror film, perhaps because it demonstrates the characters' nightmares. The Dream Dimension from Nightmare also helps to corroborate a confusion that would involve the Multiverse.

Furthermore, Agnes, who at this point in the championship, is in the face of being Agatha Harkness, would be an ally, or at least a forced ally of the villain, and whom she refers to as her husband Ralph, who never gives guys, including her saying that he looks better in the dark being an indication of that. Westview residents, by the way, may be threatened by their fears, which is why Herb was so tense when he almost revealed the truth to Vision in the third episode.

Among other things that help to corroborate this theory is that in the comics the Nightmare is part of a group called The Six Fingered Hand, formed by six demons. This would be alluded to in the series through the mysterious hexagons, which have SIX sides. In addition, minions of the demon Mephisto are part of this group, so I do not rule out the presence of this villain, who is so much speculated.

Another thing is the music that plays in most of the trailers called "Daydream Believer" by The Monkees. The lyrics refer precisely to a person who daydreams, which is what would be happening to Wanda! AND CALM THAT HAS MORE.

In the third episode of the series, there is a commercial for the series about a HYDRA soak, which had already been mentioned in Agents of S.H.I.E.L.D. In a recent Entertainment Tonight interview with series producer Jac Schaeffer, you can see the producer wanting to deviate from the subject of "WandaVision" having more connections with Agents of S.H.I.E.L.D,:

Entertainment Tonight: “Fans connected the most recent commercial for Hydra Soak to an episode of Agents of S.H.I.E.L.D., which would be one of the few times the MCU has connected back to those Marvel shows. Was that an intentional connection? Are they sniffing in the right spots there?

Jac Schaeffer: “This is where I'm going to talk about something entirely different. What can we talk about? [Laughs] It rained yesterday!””

WHAT DOES THIS RELATE TO "WANDAVISION"? In the fifth season of Agents of S.H.I.E.L.D., the agents end up opening a gap for the Fear Dimension, in which manifestations of their worst fears eventually emerge. The Nightmare is a being that feeds on these fears, so what if the Fear Dimension and the Dream Dimension are the same? Something similar has already happened between "Cloak & Dagger" and "Runaways", where we discovered that Darkforce DImension and Dark Dimension were the same place.

AND MORE! During the sixth season of Agents of S.H.I.E.L.D., the villain Izel emerged as a being from that realm looking to inhabit bodies for the residents there, as they were incorporeal beings, at the end of the season, she actually tries to bring them to reality. Which would not be very different from what Nightmare would be trying to do, which would be reaching our reality or at least merging its dimension into ours.

What did you think? Comment!! (Sorry for any grammatical errors, english is not my mother language).