Shadowfire (1978) is the second novel in The Birthgrave Trilogy by Tanith Lee. Vazkor, Son of Vazkor is it's US title.
I saw her, hanging in the sky like a flake of the moon. A woman, her face masked by a black
shireen, her body by a black shift, but her white arms spread, and her white, white, bone-white hair blowing all around her like a flame composed of smoke. Recognition was immediate. It was my mother. I shouted at her. It was crystal clear to me, what he had meant for me, my father, Vazkor, what she had robbed me of. And I drew from my belt my hunting knife and threw it at her heart.
The son of Karrakaz and Vazkor grows to manhood among the tribes, eventually awaking to his real personhood. Chased by those who wish revenge on the son of Vazkor, who started a war which vanquished their cities, he must evade his hunters and seek for his mother, the white haired woman known as Uastis the goddess of White Desert.