X'chll'at-aa, the Lord of the Great Old Ones, the Unborn God, and the Enemy of all that Live. It appears as a human fetus but grotesque in appearance. Arguably the most powerful Great Old One within the pantheon, nearly equal in power to an Outer God.
It is unknown where X'chll'at-aa resides, but many suspect it to thrive within the "Womb of the Dark Sun". It lives in a location of where a black inky sun supports Elditrch life much like the human's sun support their own.
X'chll'at-aa is believed to one day rule the universe alongside it subordinates, or perhaps even destroy it in order to create another more twisted version of our universe, for the Old Ones to thrive within.