#uthuluc

Which isn't too surprising considering that, much like Kathool, they take inspiration from Cthulhu, a Great Old One from the Lovecraft Mythos, who in turn had their own cult of worshippers.

What is surprising though is how exactly they got acolytes to begin with and what their core beliefs are given, as the flavor text points out, Uthuluc simply devours all who would approach it. An acolyte is usually someone who carries out religious duties within a religion. Aiding in specific rites and such. Which begs the question, what rites are they trying to pull off? Do they simply believe that offering up their souls to Uthuluc is what they must do in order to please their god? Do they believe they must be unleashed upon the world to achieve some end goal? What does Uthuluc ultimately want?

If we are going off old dev quotes, which of course must be taken with a grain of salt, Uthuluc was the original, and only, inhabitant of the empty space that was the Plane of Elemental Spirits until of course the events surrounding Tainslav's Last Will take place and suddenly this primordial entity is forced to share its residency with a bunch of human elemental souls. Souls it can devour and presumably destroy forever by doing so if we are to take Kathool's ability to degrade the souls of their victims as an example of the deconstructive effect Primordial entities like them can have on one's spirit.

Eventually, at some point, this creature is, somehow, locked away for an unknown amount of time until around the time the Hero is sent into the PoES to find an elemental spirit companion to bond with. They are eventually freed not long after that by Pandora, accidently, and then subsequently locked away again by Aegis and the Hero working together.

Now in cut content for Void Ship apparently their new prison didn't last long and eventually they managed to somehow find their way into the Void though I suspect now the reveal of the Nicborn paradigm of the Plane of Elemental Spirits answers that question for us as to how they managed to slip out of the space into somewhere else entirely if they were supposed to still end up in the Void.