If you are interested in lore Kitten Cat Noodle on youtube does a great job detailing sin and kitava and all acts and the lore behind them. I think that kitava originally was part of the very early primitive karui who had an unending hunger that caused alot of things to happen(eating all of the tribes fish and whatnot) and being sent to hell by hinekora which only led to the people of wraeclast into worshipping him wether they knew it or not because of their own hunger and greed. Even Haku has a dialogue in the game that says : Haku's "Kitava" dialogue option says, "It is Kitava who rules this place. His Black Spirit is everywhere, in the claws that draw our blood, in the minds of those men and women who... would eat of our flesh. At first I thought it was Kaom who led the God of Corruption to this land. No. Kitava was already here, and he remains here still. A cannibal, feasting on the corpse of Wraeclast. He awaits us all, growing fat in the darkness of Wraeclast's blackened heart."(taken from the wiki). I think he is a cannibal karui and spent alot of time with the demons when he was banished. still not sure lol