@typical_demigod Rae-eon is a weapon of sorts. He is still very much a person, but he was turned into a Soul Vessel by a collaboration of Wizards and Sorcerers for a particular purpose. He is among the first 5 Soul Vessels to ever be created and perhaps the last. This is the same most other mythical beings/creatures come into my world. Usually for war efforts. For example Sirens were made on the premise of destroying armadas in a single night. Now that war is long over, and siren's plague the seas.
We are still world building, but lots of creatures will be created this way. Soul Vessels just happen to be a soulless soul eaters. When they kill someone they take that persons soul, and they can then use it for energy to do more magic. So instead of getting fatigued like most magical users, as longs as they have souls to burn, they can continue doing magic. This makes them wildly powerful, but there is lot more too them that I'm not going to add into this, for it would be too long.
However, I will say that there are quite a lot of downsides to being a Soul Vessel that Eon and the others will have to figure for themselves as time goes on!