In the files, the ‘???’ entity is referred to as being Empty in some way. (I’m pretty sure that was a whole thing, but it’s been awhile.) I, however, personally dislike this and made my own thing before that was discovered anyway.
The Game-Master/Game Master/Gamemaster (I don’t care how you spell it) is an overly powerful being that finds enjoyment in the torment of any who it deems ‘lesser’ to it. It has taken over the private estate of a rich family, transforming their manor into its own ‘game board’ if you will. This entire area can be freely manipulated by the Game-Master, like an ever changing jigsaw puzzle. It uses this place to trap people and force them into it’s game.
However, as any good semi-tangible Eldridge being knows, you need pawns to act out your will on the physical world. This is where the previously mentioned family comes in, it’s wicked power morphs their mind and body to its will, transforming the family members into crooked monsters to chase and kill any game participants.
They was but one factor the Game-Master didn’t account for; the sudden introduction of the Yeep race into a formerly Gnome populated world. Even with their superior strength and will, they were still lesser to the Game-Master, and as such they were subject to its sick game. The Yeeps, however, overcame its challenges one by one, and were slowly but surely making their way to being deemed equal to the Game-Master. As they progressed the creature gave them gifts as a token of its respect for their soon-to-be equals.
I feel like this well explains every aspect of the Horror updates. If there’s anything I missed please let me know, I enjoy world building and had a lot of fun coming up with ideas for this interpretation!