Source of Divine Power
When simplified, a Divine Domain is a collective of Sophontic Souls dedicated to a specific idea, concept, or object used as a source of power by a Divine being. Domains can be thought of as limitless sources of power due to Sophontic Soul's ability to slowly regenerate their intrinsic energy known to the Cosmos as Faith. The complexity of Domains becomes apparent when one starts to realize the sheer diversity in their potential concepts, from the simplistic concepts of the sea and fire to the more esoteric ones such as hope and honor.
The power available in each Domain is dependent on the number of dedicated Souls that currently reside within it. When a sophontic creature dedicates themselves to a Divine through worship, they effectively pledge their Sophontic Soul to that Divine. Upon death, their chosen Divine pulls their bodiless Sophontic Soul into a Domain they control. Many of the afterlives purposed by religions across the Cosmos are rooted in some measure of truth. Indeed, many Sophontic Souls attain final rest in a paradise of their deity's creation.
On Ravare, the rules have been slightly changed. Under the watchful eyes of Lady Death and her Angels, all Sophontic Souls first pass through to her Domain of the Dead to be drained of their power before being sent to the Domain they rightfully belong. This does not technically damage the Soul in any way, but does make the Soul functionally useless for several years until it has enough Faith to be useful.
This article is only known to Clerics.
Despite the immense power held within Domains, a Divine can only extract Faith from it equivalent to the number of their living worshippers. Thus, if a Divine no longer has a dedicated following, they are effectively castrated of their Divine power and pose easy targets for ambitious Divines and mortals alike.
It is common for many Divines to share a single Domain. This mutual control has the benefit of allowing the Domain to build-up quickly as various cultures give their Faith to each Divine. However, this also leads to deific disputes between Divines within the same Realm as this division forces them to learn to share their living worshippers with each other.