Warning: This article contains spoilers for Stranger Things season 4.
A new StrangerThings theory claims that season 4's villain Vecna has been the mastermind pulling the strings in the Upside Down since the very beginning. Introduced inseason 4, Vecna (Jamie Campell-Bower) is later revealed to have been exiled to the Upside Down by Eleven (Millie Bobby Brown) after he killed the kids at Hawkins Lab. Subtle hints in seasons 1-3 suggest that Vecna isn't a late addition to Stranger Things, but actually the secret big bad who's been pulling the strings all along.
In the 1950s, Victor Creel and his family move into a sizeable home in Hawkins, Indiana after coming into some money. Victor grows to suspect that the house they'd moved into is haunted by some demonic presence, misidentifying his son Henry's budding psychic powers as an outside influence. Before long, Henry becomes disaffected with humanity as a whole and kills his sister and mother, fainting before he's able to finish off his father. Victor is convicted for the murders and Henry is turned over to Dr. Martin Brenner, becoming One and being set on a path that would eventually have him stuck in the Upside Down as Vecna.
Related: Why Stranger Things Creators Have Regrets About One Season 4 Death
With the revelation that Vecna has been in the Upside Down since long before the start of the series, there is a very real possibility that he's been actively trying to escape since Eleven accidentally opened the portal to the upside in Stranger Things season 1. Though the series offers up the idea that Vecna is a sort of five-star general for the Mind Flayer, there are hints that this might not be the case. Vecna was planned by the Duffer Brothers since season 1 (via Netflix
Read more on screenrant.com