UNDERSPACES
Underspaces are a type of space in this world that are a level deeper than what regular people can see. They can be entered through breaches. Those don't typically appear by accident and had to be opened specially by the keepers of each space.
NEGATIVE SPACE
The biggest underspace out there is the Negative Space. It is the tangible manifestation of the parts of our world where nothing is located. It's the space between the objects, and even between the molecules of air. The positive space still takes up all the space that it does in the normal world, and it looks like nothing but can still be interacted with. One of the things you can do there is open doors that lead to the regular world. One person is present there right now, but is it even a person anymore?
Art
The space
Note that these are only initial concepts and it will probably end up looking a lot different!
The keeper
REDIRECTION
Since in this world, souls need to be posessing a vessel to exist in the physical, when they exit a dead body they end up at the only place where their state is possible, which is the Redirection. They get a temporary vessel in which they are sent to the Bliss. The keeper of the redirection tries their best to make the shift as gentle and peacuful as possible for the distressed, confused people that come there. The time flows much differently in the Redirection so that the keeper can navigate every soul at their own pace.
Art
The space
To send away a soul, Caisyn leads them to one of the doors and blows a giant bubble into the void that is behind it. They enter the bubble and then travel upwards into the soul stream, almost like an elevator.
The keeper
BLISS
The destination of the bubbles from Redirection, Bliss. This is what some people mean when they say Heaven. There's not much to be said about it. Nobody comes back to tell.
Art
The space
Bliss isn't really a fixed image. It's just a space where you feel the safest, with all the people you loved that already got there too.
DREAMSCAPE
The one space more common people are somewhat aware of. Dreamscape is an empty canvas where some people's minds wander when their body is dormant. The dreams they see are either a manifestation of their own experiences or something the keeper has been up to. They [the keeper] like messing with the dreamscape; it's their art. While not all people see dreams, all the keepers have a guaranteed ability to go there, although they might choose not to. Sometimes it serves as a meeting spot. The keeper likes to keep in touch with them as well.
Art
The space
As said before, dreamscape can be anything. However, it does have a dormant "default" state.
The keeper
Additional
The keepers and the blame between them