[Disclaimer: In the end everything will make sense, just stay with me. By OC I mean the conclusions I drew from all of this and how I connected it]

Hear me out, this could be big and it will proof my theory (you will read in the following) in big parts!

"An Alhoon is an illithid Lich." (Vecna)

"Vecnas name, as you might know, comes from the Demilich of the same name in D&D. Liches are powerful undead wizards". (reply of u/brentus86 on my first post about this theory which motivated me to dig deeper)

There are several kind of Liches in the D&D universe but there is one SPECIAL one, an ALHOON. Why is he special? Well, an Alhoon is Illithid which is a term from the ELDER BRAIN universe! Illithid is a synonym for MIND FLAYER.

AND there is one thing about Alhoons that is also important. VERY important:

> Alhoons were magic-using outcasts from mind flayer societies who had defied the ruling elder brains to achieve a limited form of lichdom. Only the most powerful mind flayer mages could achieve true lichdom and were known as illithiliches.

> Their powerful combination of arcane magic and psionics led them to become a threat to the established order of the Underdark and beyond as of the mid-to-late 14th century DR.[5] They spurned the elder brains who ruled illithid societies, and had no qualms about mentally enslaving illithids, a taboo in mind flayer society.

This means that Vecna would indeed be a Mind Flayer, but a special one, that might act against the will of the Elder Brain we know as Mind Flayer.

​

Lets dive into the World of Mind Flayers, the Elder Brain and why the terms matter in the end

First of all: The Mind Flayer of the series much likely isn’t based on the usual definition of an Mind Flayer, but on an Elder Brain (Ilsensine). In the series and in the Stranger Things Wiki "The Mind Flayer" as we know it is also referred to as "The Brain" and it resembles the definition of the "Elder Brain" very much.

Here are some informations about the creatures and the similarities to the Stranger Things Universe:

1. The Mind Flayer of the series acts like an Elder Brain (aka Ilsensine)

The Elder Brain is characterized like this:

• It got strong mind effecting powers (Like what we call "Mind Flayer" in the series)
• Its favourite terrain is underground (Like the tunnels in season 2) and it lives in the Underdark
• It uses rats as a favourite host (Like in Season 3, Episode 1, 30:40)
• It is the leader of the Mind Flayers (creatures similar to Vecna) and the species they enslave (Troglodytes - similar to Demogorgons and Humans in the form of the Flayed)
• The Elder Brain served as the center of the communication network, relaying information received from one mind flayer to the entire colony, storing all the collective knowledge of the colony, and issuing commands to individual mind flayers. The degree of control and organization exerted by the elder brain over a mind flayer community was so absolute that it was more convenient to think of a mind flayer colony as a single individual: the elder brain.
• It uses tendrils to lash out at or grapple opponents (Like in season 2)
• It possessed infinite tentacles of infinite length that stretched to all planes

​

2. Vecna acts like a Mind Flayer per original definition

Here is how the Mind Flayers of the Elder Brain are characterized:

• They consumed their victims' very personality by extracting and devouring their brains while they were still alive (like Vecna did with all his victims, consuming their power)
• Mind flayers had preferences for specific types of brains. For example, free individuals were more satisfying than thralls, with the thrilling lives of adventurers ranking their brains highly. (Or Brains of people with a traumatic past, like Vecna does prefere)
• They are usually the underlings of the Elder Brain
• These alien entities sought to expand their dominion over all other lifeforms, controlling their minds to use them as obedient thralls
• The control over them is centralized by an elder brain, a singular entity that exerted its telepathic control simultaneously over all mind flayers

​

1. The Demogorgons act like Troglodytes which are, in the world of the Elder Brain, an enslaved species used as foot soldiers.

Here are characteristics of Troglodytes:

• They are "hunting weaker sentient beings before dragging them back to their caves" like the Demogorgons do with their prey, bringing them into the Upside Down (their cave)
• They fight " with tooth and claw"
• They had a strong preference for human meat
• Their sense of smell is incredibly powerful
• Their lack of intelligence made them easy to control by mind spells

They actually used close to nothing from the description of the D&D Demogorgon

> The demon towered a full 18 feet (5.5 meters) in height,[1] his body at once sinuous like that of a snake and powerful like that of a great ape. Two baleful baboon heads, with blue and red faces similar to those of mandrills,[1][18] leered from atop his lumbering shoulders, from which two long tentacles writhed. His lower torso was saurian, like some great reptile with blue-green, scaly skin. He had an immense forked tail

> Demogorgon preferred to avoid direct conflict, instead using magic to help his servants.Demogorgon could hypnotize with a gaze[1] or drive creatures around him to terror and insanity just at the sight of him. His whip-like tail had the ability to drain the life energy right out of a living foe.

> Each of Demogorgon's heads had its own name and personality, a duality that created an enduring internal conflict of his personality, while shaping all his actions and even his realm

The Demogorgons in the series act way more like Troglodytes from the Elder Brain Universe than a original D&D Demogorgon.

​

1. Liches like Vecna are powerful undead wizards whos home is the Prime Material Plane

• which is important since "the Prime Material plane occupied an important position as a crossroads of the multiverse."
• They also mention "Portals" and the Plane of Shadow which is a term the boys use for the Upside Down.

Thoughts

If this is true, there are a few things we can draw from this:

1. The Demogorgons are a species that got enslaved by the Elder Brain/Mind Flayer, like the Flayed in the human world. The detail of them dying without a connection to the Upside Down and The Elder Brain seems to be added. Their brutal nature is natural and not added by the Elder Brain.
2. Vecna is no underling of the Elder Brain when the Alhoon-Theory is right.
3. The "Mind Flayer" is in fact an Elder Brain, a way stronger being than we thought. A being that probably infects worlds to take over the beings to enslave them entirely.
4. There could be other "real" Mind Flayers like Vecna under the control of the Elder Brain. Since we dont know where One/Vecna has his powers from we cant know how much humans with such powers there are, who could be diverted into an (by original definition) Mind Flayer
5. This would also add much details for fan theories
6. I think they simplified it cause it is easier for the storytelling. Instead of several different antagonists you have one at a time and per season (Demogorgon S1, Mind Flayer and his foot soldiers S2, Mind Flayer S3, Vecna S4). This is way better to handle than a complex society as an antagonist.

Why I think that Vecna isn't the final boss:

[Storytelling]

From the storytelling point it actually would make more sense for Vecna to be the puppet of the Elder Brain. Here is why:

You had the first season starting with the Demogorgon (one foot soldier), the second season got more intense with Will being infected and the Demodogs showing that the Elder Brain has an army. Then you get another step of escalation by adding an entire group of humans (the Flayed) to be infected as well as the Rats and the huge makeshift monsters of the Elder Brain consisting of dead beings (the Elder Brain by definition often consists of a pile of dead beings). There is a huge build up which leads to a showdown in the middle of the planned project (Season 3 of 5). We had a hard drop after the final of season 3 since the big fight overshadowed everything and they build up a new plotline in season 4. Season 3 is the preparation for season 5, like 2 was for 3. Season 1 was just the introduction to the universe.

[Power]

If you look at the powers the Elder Brain (Mind Flayer) is way more powerful than Vecna. Vecna can use some of the Elder Brains abilitys like the tendrils, but overall nothing controls the minds and the creatures like the Elder Brain did in season 2 and 3. It controlled a vast amount of Demodogs, flayed Humans and makeshift creatures. Vecna usually takes on one person at once.

It would also be hard to believe that Vecna build all of this. Think about it: If it was Vecna all along, he would have to overthrow the Demogorgons, create the Mind Flayer and have a reason to not show up in the human world for 3 seasons despite everything that happend.

All in all Vecna seems to have got most of his new powers and abilites from the Elder Brain which corrupted his mind over all the years he was in the Upside Down.

--> If Vecna would be the real antagonist, the build up of the series would have been different since you build a long story like that with two finals (one in the middle and one at the end) and you would have to explain him being absent for 3 seasons. I think he is a general and will remain some. Everything else would be too complicated to sell to the audience.

Edit: All of this is purely speculative. I'm looking forward to your thoughts on this!