Locomotion, Ethel and Winthrop are the same type of being: immortal entities that preside over a pocket dimension. The main thing that differs between them is their stage in the lifespan.
Ethel is young. Not by human standards, of course, but by the standards of an entity like this, she's practically a newborn. She is only just beginning to develop an identity, and she likely isn't aware of any others of her kind. Her domain is very barebones so far, just a series of dark rooms (and one facsimile of Bristol), and she only has two permanent residents - though she has put in the work to Change them much faster than normal. In line with her relative youth, her domain is experimental, filled with madness and hedonism and violence without death.
Winthrop is mature. He's been doing this for some time now, and his domain has taken on a very strong identity - one reminiscent of Jim Henson's Labyrinth. Winthrop is also an experimenter; but unlike Ethel, whose experiments are based on youth and feeling out the boundaries of her abilities, Winthrop's experiments are those of one who has grown tired of the real and the mundane in its entirety, and will try anything to bring back the spark. Sapient eggs that sense movement. Doppelgangers that seem to know that they are doppelgangers and try to kill the original. People who are half man, half creature (crams). Winthrop is having a sort of cosmic mid-life crisis - and his game of truth and tea is a desperate gambit to find some meaning in all of it, to disprove what he already cannot help but believe: that suffering is the universal human condition. Even if you're not really human anymore.
Locomotion is old. Very, very old. Older than the devil. Unlike Ethel and Winthrop, who were at one point human, Locomotion was formed into existence wholesale, close to the beginning of humanity itself, an avatar of travel, a nightmare child. Perhaps this is the name of these creatures as a whole. Perhaps Locomotion was even the first. One must wonder, then, why we don't see more people in his domain. After all, he's been doing this for a very long time. Perhaps, then, his domain is simply a connecting line between the domains of other nightmare children. Those that cannot catch enough people to sustain themselves receive an express train from elsewhere. And so on, and so forth.
I feel like there could be more. Fledgling nightmare children whose domains have not yet come into their own. Perhaps the Bluebell King, or the Spirit of Somerset. Imagine what they could look like at their full potential.
WAOH okay I'm adopting this instantly. nightmare children meetup fellas, all of this is actually so well made wtf dude. ethel's mayhem, winthrop's defiance, locomotion's eternity AUGH this is. amazing. bluebell king or spirit domain would be so cool toooo