Every universe is made up of realms, usually a living realm or two, an afterlife, and a FaeRealm of some sort. Universes are more likely to cluster together than not.
Universes are made when someone in the GodMachine makes a fictional world, accessing the well of all creativity known as The void of creation.
Universes are made of realms, such as realities, afterlives, faerealms deadrealms, and prison realms.
Reapers are usually people from afterlives that leave to get ghosts out of Etheria and into the afterlife.
Some afterlives are parasitic in nature, often independent from any universe, these afterlives drift near universes and siphon souls from a reality's Etheria without using reapers
Most afterlives have no split between Physica and Etheria.
Any archfae realm in a universe with a faerealm will be connected with it.
Whatever the reason, these universes are to be avoided at all costs. Some multiverse wanderers have gone as far to remove entire universes from their chart because they had a deadrealm.
These are also avoided by multiverse wanderers, for obvious reasons.