When a mortal dies, their soul energy is sent to a Soul Gathering System matching their alignment energy types. Once there, in a System far beyond the Mortal Systems, they are reincarnated, usually forgetting everything of their mortal existence.
There are so-called "evil systems" which really means they are a concentration for certain energy types, like negative entropy and unholy energy for the Nine Hells. "Goodly systems" like Arborea serve as a focus for entropic energy and holy energy.
Once in a Soul Gathering System, the soul energy of the dead is re-purposed. In the Nine Hells, this energy goes into the creation of more devils. In the Abyss, spawning lakes churn with souls getting their first taste of torture, if they fight their way out, they become demons. Those souls that go to good and neutral systems, Arborea, Elysium, Equipoise, Nawenglorûs, and Nirvana end up in a broader category of non-mortals called the celestials. The term angels is also used, but usually only when referring to the celestials of Nawenglorûs.