One of the major questions surrounding Stranger Things season 4 was the origins of the Upside Down. The creators of the sci-fi series had not revealed much about the parallel universe. But thanks to the new season, we have got more information.
We were first introduced to the Upside Down when Eleven accidentally made contact with Demogogrgon and opened a gate between both worlds. Will was somehow teleported to the Upside Down. Now we got to know it’s a dark parallel mirror dimension of the real world. At the end of the season, Eleven used her powers to banish Demogorgon back to the Upside Down.
In season 4, Hawkins is under attack again by another monster Vecna from the Upside Down. As the season goes on, we find out that Vecna is a general in the Mind Flayer’s army who is tasked with creating new gates to Hawkins. Vecna was able to create portals through psychic contact with his victims because we learn that Vecna is One (Jamie Campbell Bower), the first child of Brenner’s program. He developed psychic abilities as a child, and Brenner used him for his program.
In chapter 7, Eleven banishes Vecna to the Upside Down in the same way she banishes the Demogorgon from season one. Thus One is transformed into Vecna. Just like Eleven, Vecna also has psychic powers which he uses to contact across dimensions.
In another scene, Nancy went back to her house to arm herself. However, her guns aren’t in her bedroom, because as she realizes, this version of her bedroom is from November 6, 1983. It was the night that Eleven opened the first portal and Will went missing. It means that the Upside Down is stuck in 1983.
But there are some burning questions still left to answer.
Was the Upside Down existed before Eleven opened the first portal? Did Eleven actually create the Upside Down? Also if Eleven created the parallel world, how did she know every detail of Nancy's diary? In one scene Dustin said that the Upside Down might have existed for thousands of years. So it could have been there for much longer than we thought earlier.
What are your thoughts on the Upside Down origins? Let us know in the comments section.
I think the Upside Down exists for thousands of years, like another Universe and perhaps there are more Universes, and this is just one of them. Perhaps the reason why The Upside Down World is stuck in 1983 is because of Eleven: maybe somehow the time stopped the day she opened the gate between the two worlds. Or maybe Vecna is just messing around with the time, as he said that he didn’t like the idea of time, so he makes his own rules, leaving the Upside Down on 6th November 1983.
The closest we can come to answering this right now is to look at the Shadowfell and Ethereal Plane from D&D which are the obvious inspiration. The Shadowfell is a warped mirror that leads to other times and places and itself is bled into by the Negative Energy Plane. The Ethereal Plane holds on to images of other times which slowly decay making it possible to see back in time. The Upside Down appears to have slower moving time but be slowly decaying and definitely pure evil exists in the realm
A huge portion of this the upside down in this season revolve around the grandfather clock. Time seems to have a serious importance to Vecna and the therapist has the key to the clock on her neck. There's likely some relation to Vecna and time and locking time in place for some reason
Henry (via Henry, himself & Billy) mentioned that "We have been building", suggesting that he isn't alone in the Upside Down, but also that he has changed the dynamics of it, & his ability to control &/or use time has allowed him to do so. If I'm not mistaken...Steve & Nancy were together in her room the evening AFTER Will went missing. Whether that's a plothole or something else I'm not so sure.