Devourers are beings from outside the universe that devour or eat life energy. This dimension that they come from is known as the Gray, it is a place where souls are reshaped and reformed into entirely different beings, similar to the spirit realm, however the spirit realm is accessed via spells and wards unlike the gray which can only be accessed by souls after death and contains beings comprised of pure energy and beings that have lost their purpose(these are usually organisms that have died via unusual means such as sacrifice or curses as well as lost souls who long to live again). The beings made of pure energy are actually made up of a kind of energy called Aether. Aether is the energy used by gods to create and destroy, it is also the foundation on which souls are created. This energy is very powerful and allows for various reactions. These beings that live in the Gray feed on this energy as well as the other components of a soul. So when Miod being god of death, always resides in the Gray, however when he was defeated by Yieldred, his connection to the Aeth Realm(A space in between realms that contains vasts amounts of Aether. It is where gods draw their powers from, the gods themselves are also made of pure Aether.)was severed. Miod now had to use the little power he had left to prevent Yieldred from interfering with his new plan. So Miod was able to use his power to split Yieldred into five separate gods. Valstrom, Celestia, Maal, Argus, Ren and Zerosa.