Warning: Spoilers for the first two episodes of WandaVision are ahead.
Someone is watching Wanda and Vision on WandaVision. The only clue in the Disney+ series premiere episodes is a pointy, sword-shaped symbol that keeps popping up. While you don't necessarily need to read a ton of comics or rewatch all the Marvel movies in order to enjoy WandaVision, it might help to get a little inside info on that symbol and why it's so dang important.
The symbol is first spotted in the control room at the end of the first episode on the wall and the notebook in which someone has been taking notes on the "episode" of Wanda (Elizabeth Olsen) and Vision (Paul Bettany)'s life in the suburbs. In the second episode, it appears on a toy helicopter and a super creepy bee keeper that intrude on this carefully constructed fantasy world that the Scarlet Witch, or someone else, has created.
While this is the first time that this symbol has officially shown up in the Marvel Cinematic Universe, comic book fans know what's up. This is the logo for S.W.O.R.D., which in Marvel comics stands for "Sentient World Observation and Response Division." It's a government organization similar to the ones we've seen before in Marvel comics and movies.
You remember S.H.I.E.L.D. from the Marvel movies, right? It stands for "Strategic Homeland Intervention, Enforcement and Logistics Division." Characters in Thor and Iron Man used to make fun of Phil Coulson (Clark Gregg) for the name. We know S.H.I.E.L.D. was co-founded by Captain America's once (and future?) girlfriend, Peggy Carter (Hayley Atwell) and that ABC had a whole show about the Agents of S.H.I.E.L.D. They're the good government guys, except for that one time in Captain America: The Winter Soldier when it was revealed S.H.I.E.L.D. had been infiltrated by the fascist Nazi organization, Hydra. What a crazy, fictional plot that only a comic book could cook up.
What is S.W.O.R.D.?
Anyway, S.W.O.R.D. is essentially S.H.I.E.L.D. in space. Or, so we think. On WandaVision, it appears that S.W.O.R.D. stands for "Sentient Weapon Observation and Response Division" — an assumption fans gathered from trading cards and promotional images. This small difference might be nothing, but it could also be everything. The phrase "sentient worlds" clearly refers to extraterrestrial intelligence, but the phrase "sentient weapons" is more like... a magic wand with a mind of its own, or an "unusual couple" capable of being weaponized themselves. Maybe, on this show, S.W.O.R.D. has nothing to do with space. Or maybe Wanda is trapped on an alien planet. We just don't know.
One thing we do know is that S.W.O.R.D. seems to be the connective thread between the three seemingly random MCU characters we know we'll see in WandaVision: former S.H.I.E.L.D. agent Jimmy Woo (Randall Park) from the Ant-Man movies, former research assistant Darcy Lewis (Kat Dennings) from the Thor movies, and a grown-up Monica Rambeau (Teyonah Parris) from Captain Marvel. Two of those three characters — Monica and Darcy — get up to some space and alien stuff in the MCU, which leads us to...
S.W.O.R.D.'s role in Marvel comics
The organization was first mentioned in an Astonishing X-Men issue written by Avengers director Joss Whedon, interestingly enough. Later, a spin-off comic about the Agents of S.W.O.R.D. was released in 2009.
The S.W.O.R.D. comics are about a mutant named Abigail Brand who has green hair and hot hands. (That's her superpower; her fingers can burst into flames.) She is the co-director of S.H.I.E.L.D. and works to protect Earth in space with her boyfriend, X-Men dreamboat Dr. Hank McCoy, also known as Beast, the furry blue mutant who was played by Kelsey Grammer and Nicholas Hoult on the big screen. She also has a troublesome alien half-brother.
S.W.O.R.D. operates out of a space station called The Peak that is shaped like, well, a sword. They're officially a counterterrorism and intelligence agency. If you're getting Space Force vibes, you're not wrong. But unlike our universe, the Marvel universe actually needs counterterrorism in space. Also, this space force is pro-alien rights and fight back against those who seek to deport them. "We're not just here to save Earth from the aliens," Abigail says in issue five, "we're here to save the aliens from Earth."
S.W.O.R.D. has (kind of) been in the MCU before
There have been three hints and nods at S.W.O.R.D. in the Marvel Cinematic Universe thus far, but none of them have been super direct. The first mention of S.W.O.R.D. was in a Thor deleted scene/alternate ending, in which Dr. Erik Selvig (Stellan Skarsgard) puts together a team and asks that they cross-reference S.H.I.E.L.D. data with S.W.O.R.D. data. But you're not likely to know about that scene unless you're super into DVD extras, so it's not that official.
Then, in the second post-credits scene at the end of Spider-Man: Far From Home, we see Nick Fury (Samuel L. Jackson) chilling out, maxing, and relaxing on a space station that looks suspiciously like The Peak from the S.W.O.R.D. comics. He's there while the two Skrull aliens from Captain Marvel pretend to be him and his partner Maria Hill (Cobie Smulders) on Earth.
The S.W.O.R.D. symbol we see on WandaVision does not appear on Skye's spaceship in the episode, but the work they're doing sounds awfully similar. Oh, and Skye also has a troublesome half-sister joining her on this space mission. Curious.
The Agents of S.H.I.E.L.D. producers have non-committedly referenced S.W.O.R.D. as potential spin-off material in interviews, and the character Yo-Yo joked in season 5 that S.H.I.E.L.D. should have "a space division called S.P.E.A.R. or something," but nothing official ever manifested.
What is S.W.O.R.D. doing in WandaVision?
That is the million dollar question. This could be where the big "sentient weapon" thing comes in. It could also be that this organization is trying to study Wanda's powers, and has put her in a simulation. It should also be noted that in episode 2, Wanda heard a voice on the radio that sounds a lot like Park repeatedly asking "who is doing this to you" — which could mean they're trying to help her.