With the official trailer for Stranger Things' fourth season having been released fans are rummaging through the video for secrets and clues about the characters' fates. With Eleven and the Byers family having moved to California at the end of Season 3, the teens are all split up; however, it's clear the Upside Down isn't done with them. The trailer teases a lot of macabre violence -- and even death -- once they reunite.
The popular Netflix series is moving into adult horror territory, so themes of growth and maturity would be appropriate. There are a couple of scenes in the trailer that indicate the series may be allowing one important character to find a much-deserved path to redemption. However, it would come from the afterlife.
Billy Hargrove was used as the human avatar for the Mind Flayer in Season 3. He was under its mind control and got other brainwashed people to become the Meat Monster, but eventually broke that control and sacrificed himself versus the giant creature in the Starcourt Mall battle. This helped save the group, including his younger sister Max -- allowing her to see that he wasn't as big a jerk and bully as she (and the viewers) thought.
The possibility of Billy returning in Season 4 is hinted at when the trailer opens up with Max mourning at his grave (including a small mistake). Shockingly, later on, at around the 2:37 mark, Max can be spotted levitating in the cemetery, so that could be due to Billy. The prevalent theory that's emerged since the trailer's release is that Stranger Things' new villain Vecna (who was created with practical effects) may take Billy as its form, given his connection to the Upside Down. If so, that also means the good part of Billy would also still exist in the spirit realm.
If Vecna uses him as a vessel in the dark dimension and pieces of Billy are indeed revived, while his rage and darkness could fuel Vecna, his love for Max might trickle through the rift and empower her. That would give Billy an important role in Season 4. Knowing Eleven doesn't have her abilities, Billy's soul could make Max the new weapon to fight monsters from the other side. It'd be a weird curveball, but one that adds nuance, given all that Max wanted was for Billy to be a good brother.
Even their parents saw Billy as a monster -- which is why the Mind Flayer easily corrupted him when he got physically abused at home for his insolence. Maybe a repentant Billy (or whatever remains of him) wants to be proactive rather than reactive, and in helping out during Season 4, he could earn some redemption for his possessed experiences during Season 3, and any other past behavior he may feel he needs to atone for. That would be an interesting arc for his character.
While he might not ever be able to physically resurrect as his old self, these powers being bestowed upon Max -- or even his ghost sending messages and helping her out -- would be the perfect way for Billy to atone. It'd grant him salvation, put his spirit at peace and show the other teens how truly sorry he is. This would also remind Max that he loved her despite their differences and push the kids on to honor him by defeating Vecna and ultimately, protect the family they all became. Stranger Things fans will have to see if their latest theory is right and Billy does indeed live again, somewhat.
To see what happens with Max and Billy, Stranger Things Season 4. Vol. 1 premieres on Netflix on May 27, and Vol. 2 arrives on July 1.