The Storm Lord by Tanith Lee (DAW)
From ISFDB:
The Storm Lord is a novel of an unknown planet and of the conflict of empires and peoples on that world. It is the story of a priestess raped and slain, of a baby born of a king and hidden among strangers, and of how that child, grown to manhood, sought his true heritage. It is a novel of alien gods and lost goddesses, of warriors and wanderers, and of vengeance long delayed.
There are a few different editions of this, but the first edition is notable for its use of the slightly obscure Soul.
