I don't think there are parallel worlds in ST, just different timelines, because for some reason they're stuck in a loop. They mention time loops a few times, and Max even mentions it when they are in Henry's house.

In S2 Nancy tells Murray that his timeline is wrong, and in his letter Hopper says that you can't turn back the clock... But then Henry does it in the flashback. There's also this Back to the future line: The appropriate question is 'When the hell are they?'

And if there's really a time loop, I think Will and Henry can see other timelines or maybe the timelines are merging? There are so many hints.

From Will's Marty Mcfly outfit in S1, to Henry seeing the Mind Flayer when he was a kid. The crystal ball in the Will the Wise drawing, used by clairvoyants, the Forever Clock that Dustin gives to Will, Will's name engraved on the grandfather clock and him saying, in his Will the Wise outfit, that he's seen into the future. If they're stuck in a time loop, then the future is actually the past, since the story has repeated itself many times. Steve and Robin even mention the whole going back to future/present thing.

In 4x01 El says that they're all time travellers, so yeah, if Olivia can see and travel to a parallel world, maybe in ST people can see (or travel to) different timelines of the timeloop.

Eleven, Twelve and Thirteen

In the Nina scenes I noticed that Thirteen is often in the frame with El or Twelve (who I think represents Will). At first I didn't understand why. She never speaks or interacts with El. And I didn't know why they cast a girl that looks like young Millie. The actress said that the crew kept telling her that she looked like Millie, and before S4 many fans speculated that she would play El. Everything means something in this show, and the casting is always on point, so I thought maybe they want us to notice something? Then I remembered that Olivia was Subject 13.

So that kid could be a subtle hint that we're seeing different timelines in Nina. From the beginning, when El wakes up and see the rooms of Four and Nine. 4+9=13

Twelve and Thirteen

Twelve and Thirteen in the Rainbow Room. It's interesting that in both these scenes they focus on 12, "Will", and 13, who looks like little El, after they show the twins. Willel, twins, and different timelines...

Brenner and Thirteen's room

Thirteen and Eleven (and Twelve)

I really think that Thirteen is a reference to Olivia, and since Olivia can see parallel worlds, maybe this is a hint at the ability to see/travel to other timelines. I already thought that El was seeing different timelines, and that she was actually there, with her mind, but this is a nice detail.

*Another interesting 13 mention. The 13th birthday of a kid named Georgie. George, like George Smith in the play? We know that Will's birthday is important, and since this scene is about his parents, I think this mention is connected to both Will and Henry/Edward

Hm, a bit lost, because of other timelines/a time loop?

Bob talks about being a little younger than Will and being at the Roane County Fair- which means that Bob was in Hawkins when this happened/likely living in Hawkins.

And moving on, the word choice in this next part is interesting- “every night he would come to me in my dreams.” (also staring at phangomgate and “in dreams he came to me”)

Why not just say “every night, I had nightmares about him,” or “every night, I dreamed about him.” Why the more complex wording? Why use wording that almost makes it sound like somebody else was physically coming into the room?

Especially with Bob talking about how he “couldnt get him out of my head,” vs very similar wording being used to describe Vecna, who has heavy sexual predator imagery.

And THIS line really made me do a double take:

Bob talking about getting his mom to physically stay in the room with him. Again, much like the “every night he would come to me in my dreams,” line, it ties back to things being physical/in the real world rather than simply in dreams- after all Bob’s mother cant protect him from dreams. So if dreams were the problem, why wasn’t Bob afraid of the act of sleeping itself? Why was he completely able to fall asleep, but only if he knew that somebody else was physically in the room?

And there’s also the fact that Bob mentioned that his mother would only stay until he fell asleep- which explains how the abuse would have continued, as Bob’s mother would leave once Bob was sleeping, and the predation would have been happening when Bob was sleeping anyway.

And we also have Bob talking about how the issues with Mr Baldo only stopped after he spoke up & told Mr Baldo to go away- which would make sense in the context of Bob being abused, and how nobody realized it was happening until he spoke up, since as he said, he would run away every other time it happened.

And how Bob never saw Mr Baldo again- almost like how if it was Father Newby bothering Bob, he may have been arrested.

Like maybe I’m insane but part of me wonders if there was ever a Mr Baldo, or if he was just added in by Bob to make the story more appropriate for Will.

Hell, I won’t be surprised if Father Newby is bald & that was why Bob made up “Mr Baldo.”

And speaking of fat, white gloves…..

The Personal Shadow

“The personal shadow is comprised of those qualities, impulses, and emotions that we cannot bear for others to see and thus cast into the hidden domain of ourselves. It is made up of the parts of ourselves we deem unacceptable. For many people this means things like our sadness, rage, laziness, and cruelty.”

Keep this above definition in mind.

"The personal shadow personifies everything that the subject refuses to acknowledge about himself and represents ‘a tight passage, a narrow door, whose painful constriction no one is spared.’”

Staring directly at the fact that the art of Henry for The First Shadow parallels the poster of Will looking out a door, at the shadow monster and there’s so much door imagery in ST. Will’s even got his shadow behind him, just like Henry does.

TLDR: a personal shadow is basically everyone’s “bad” qualities but they’re not always inherently bad.

Jekyll and Hyde are considered an example of somebody vs their shadow self/personal shadow.

“If we hold certain values and recognise these consciously then the opposite values may form part of our shadow. The shadow is not just restricted to values but the example of Dr Jekyll and Mr Hyde illustrates the point well. Dr Jekyll and Mr Hyde clearly manifested different values and these were translated into differences in their behaviours. Taking this further we can also see that sharing values would lead to a ‘shared’ shadow – the opposite of these values. The group would collectively hold unconscious and opposite values with the potential for projection.” (source)

The Collective Shadow

And so, remember how I said that I think that the Shadow Monster/the MF would play into this? Well, part of the shadow theory is something called a collective shadow.

Long story short, the collective shadow is considered the dark side of humanity, the sum of all past and present atrocities and abuses.

And we know that Henry had a whole speech about the dark side of humanity.

“The collective shadow, like the personal shadow, is relative in that it will be partially culturally determined/dependent on culture. It consists of things which opposes a culture’s conscious, shared and collective values.”

I won’t be surprised if the Shadow Monster/Mindflayer is meant to be representative of a collective shadow, a representation of the shared hateful/biogted beliefs of the people of Hawkins, a representation of all of the atrocities and abuse that’s occurred, including to people like Henry (in the lab and in the Creel house, ESPECIALLY considering the stage play being in 1959/tied to the Creels moving to Hawkins and also tied to the idea of the shadow via the title). But the people of Hawkins aren’t all inherently awful, because the shadow represents the opposite of their values/beliefs, and some peoples’ values/beliefs contradict eachother’s.

The First Shadow

So- the first shadow? It’d possibly be either a.) the first Henry/the original Henry or b.) the first new, separate sort of Henry, possibly a separate consciousness or an entirely separate Henry (staring at the Henry Creel vs Edward Creel weirdness in the Creel murder newspapers, staring at Henry Jekyll and Edward Hyde being the full names of Jekyll and Hyde). And keeping in mind that Edward Hyde was Henry Jekyll’s shadow- so then, Edward Creel would be Henry Creel’s shadow. And look at that art for the stage play again:

In this image, who is literally Henry’s shadow?

Vecna.

In the Henry Jekyll vs Edward Hyde and Henry Creel vs Edward Creel section, who was Henry Jekyll’s shadow?

Edward Hyde.

Which makes Edward Creel the shadow of Henry Creel. But Vecna is also Henry’s literal shadow in that image- oh wait, that makes both Vecna and Edward Henry’s shadow. Don’t people just have one personal shadow, though?

Yes. Because Vecna and Edward Creel are the same person. Henry Creel is not Vecna, Edward Creel is. Vecna and Edward are interchangeable, and they’re both Henry’s shadow, just like how Edward Hyde is the shadow of Henry Jekyll.

Edward is Vecna, not Henry. Even simply in a metaphorical sense, Henry is not the same as Vecna, Vecna is Henry’s shadow.

Conclusion

We’ve got the personal shadow, the collective shadow, and the first shadow.

And the personal shadow is considered the bridge to the collective shadow, in the sense that the collective shadow is made up of humanity’s personal shadows.

So, Henry’s shadow was likely the first one, the first shadow in that collective shadow- and what does the collective shadow represent? What is it comprised of? The atrocities and abuses of humanity and the values deemed negative by a culture. So, Henry himself being an outcast and being deemed negative as a child, and abused by the town and by the lab, and becoming the first atrocity in the collective shadow over Hawkins, the first personal shadow in that collective shadow.

Everything with the shadow sounds so extremely Vecna, with how he’s showing his S4 victims their own shadows, the parts of themselves that they refuse to acknowledge, the parts of themselves that conflict with their egos and ideals.

To confront one’s shadow is considered to be confronting the truth- and Jamie himself said that Vecna is fixated on truth.

And again, the collective shadow is made up of personal shadows. So, if you want to resolve the collective shadow/kill the shadow monsters, you need to resolve everyone’s personal shadows first.

Which is what Vecna was doing. He was literally forcing his victims to confront their personal shadows. He is attempting to kill and change the collective shadow of Hawkins because of how that shadow/those cultural beliefs have outcast and hurt him. But because he’s doing it by committing atrocities, he’s simply creating a new collective shadow/shifting those values/being a hypocrite. He think he’s destroying those hateful/harmful values, but instead, he’s just making his own twisted/still harmful version of them. I’ve talked repeatedly and constantly about characters like Vecna and Eddie being hypocrites and how for all of things Henry lists in his “eat sleep wake up,” monologue, he himself has his own twisted version of things, and this ties in perfectly with the collective shadow theory and the idea that Vecna is trying to destroy the collective shadow/bigotry/hate/abuse of Hawkins but is enforcing his own bigotry/hate/abuse in the process.

And going back to Henry not being Vecna, remember how the personal shadow is defined?

“It is made up of the parts of ourselves we deem unacceptable. For many people this means things like our sadness, rage, laziness, and cruelty.”

And so, if Vecna is Henry’s shadow (which, that’s exactly what we see on the poster), then that means that Vecna is comprised of things/traits that Henry deems unacceptable. Meaning that Henry didn’t share the same values as Vecna/Edward. Meaning that Henry is a good guy. Which, that doesn’t mean Edward is evil, especially not with the idea of Vecna being the result of Brenner merging himself with Edward, and Vecna and *Edward’s* values being different.

It’s also worth noting that Henry himself is very paralleled to Mairon (Sauron’s form before he became evil), and Annatar (his fake good form), but Vecna is the one paralleled to Sauron. Sauron, who poured his cruelty and his malice into the one ring. Sauron, who is described frequently as a shadow.

TLDR: timeline weirdness and Henry Creel vs Edward Creel and Edward is Vecna, Henry is not Vecna, and Henry is not responsible for Vecna’s actions.