Atrox

Atrox, sometimes "The Obscurus", sometimes "The God-King", and sometimes just "The Almighty" was once the god and ruler of Thrast, after having arrived in a time of crisis to help defeat the Fey. He was killed at the end of the war on Ekellos by Telarus, who would shortly go on to murder The Father and become one of the last remaining gods.
At some point in his life the almighty had a son, Rashall, who is currently on very bad terms with the party.
It seems as though Atrox split a part of himself off as insurance against death however his old ally Yeenoghu is now seeking to use this piece to resurrect the God-King as a corrupted version.