Ok I finally have a theory and some of this is based upon other theories that I have read here and building upon it but it’s basically an overall theory of what this place is..I’m not super good at writing my thoughts out in an organized way so bear with me lol
A pocket dimension that is controlled by an entity that feeds on human emotions and suffering, fear, and maybe even hope to a degree. It likes its food seasoned and it’s a specific recipe and it feeds every x amount of years. The OG monsters night monsters were a community that also got trapped in this dimension and were offered immortality for the sacrifice of the children..so more on this place and how I believe that it works..I think that it pulls from the fears and minds of the people who are trapped to create what exists and evolves over time..for example maybe when OG night monsters were there, they were being terrorized by things that were scary to them at the time..the buildings/structures appeared organically over time and that’s why you see things that look like they are built from the 1800s and you see things that are more modern but have electric wires that lead no where..because it’s from someone’s mind. This could also explain monsters looking like they are wearing old maids costumes..maybe this is the big overall entity piecing this together from victors mind. It could explain why Nathan ( Sara brother ) was afraid of cicadas and then cicadas came. And In my theory this is a collective thing where now cicadas would potentially also come after the next cycle of people to come through and the next etc
Anywho Tabitha and Jade were reincarnations that went against the ritual of sacrificing their child and did not receive the same immortality in the same way that the monsters did but instead must come back again and again to attempt to save the children. IMO in my theory the children weren’t the start of this dimension..this is just something that became a part of it. This entity and place is ancient.
I think the MIY is serving the entity..happily.. I don’t know if this was a person who was there and just kind of went crazy was granted powers for loyalty to the entity and “ seasoning the food” or if it is also another ancient entity but I think it’s possible that he is probably a person and it’s a role that needs to be filled. The MIY looks like an old man who may be aging out. I think it’s plausible that someone is destined to fulfill that role. But again idk! My main point about him is I don’t think he is the main antagonist.