Souls

One might wonder how sentient life of any form exists, and this is the answer, souls, of whom there is two and a half types:


 * God Souls: God souls are, interesting, to say the least unlike other types of souls, they have the ability to regenerate their mana naturally, similar almost to plants, however as a direct side effect of this, they don't have a need to inhabit a host of some kind in order to prevent disspelling.
 * Mortal Souls: unlike God Souls, a mortal soul can not generate its own mana which means one needs to get Manna from some sort of outside source (often times from eating) in order to sustain itself, which additionally means that a Mortal soul must house it, which indirectly means that a mortal soul will eventually disspel when its vessel degrades past the point of being able to house a soul.
 * Demigod Souls: really more a classification of souls than a type unto themselves, Demigod souls are mortal souls that have found a way to get a regular enough flow of straight mana (and so not damaging their vessel in order to consume it) in order to give the soul a sort of immortality, with the most common way of doing so being for a godly soul to give the demigod soul a sort of bond that means mana can flow from one to the other. although in other forms the former mortal soul might be able to "suck" mana from another soul, which is how a lich for example works, as well as things such as vampires.

Mana
often times spelt Manna, Mana is what in the end makes the the universe move, as it is not only what souls are made of, but it is also how magic is able to be used by the energy potential within Manna being used to rewrite reality in the way that the caster wants it to be, from moving a pebble with their mind, to opening a portal to another realm. although vastly different amounts of Mana would be needed in order to cast those different spells.

The Prime Soul
As all things have a beginning, all things must in the end, have an end, and so the prime soul must exist by the very virture of the cosmos itself, the wellspring of souls and also where they depart to when they die, the prime soul is if nothing else, a portal into the plane of death itself and as such much be guarded ceaselessly in order to make sure no necromancer could use its power for evil again, for which end a succession of guardians have been appointed over it, from the Archangels, to the Celestials, to the solar elves many dedicate their life to defending the only place in the cosmos that it is possible to physically enter into the plane of death.

Reincarnation
while it happens rarely, from time to time a soul upon its death, instead of returning to the "prime soul" will find a new host, usually but not always an infant still in the womb or egg that the soul can take over as its vessel and when the infant is born it will grow as normaly, sometimes with the soul retaining memories or skills from its past life(s) that it in its new life would have no way of knowing, which has allowed some souls to survive for hundreds of lifetimes, often times building religions or cults or vast fortunes around themselves.