Who are ch'thonians exactly?

It is written in the devotions that Ch'thon was thown into the void by the Empyrion to suffer eternally and that Yugol is the primordial god that is the void itself, first discovered by the Empyrion. Does that means that Ch'thon is inside Yugol? And does that means that ch'thonian void monstrosities are actually Yugol's and not Ch'thon's?