Tanith Lee 
Quest for the White Witch 

He called himself by the name of the father he had never known, Vazkor, king of a forgotten land. In his veins were mingled the blood of that regal warrior and that of his witch mother, the silver-masked, snowy-haired survivor of the hated Old Race. He had sworn that she would die at his hands in the name of his father and all that his world had become. Across that barbaric and age-haunted planet his quest went relentlessly on. As he searched, so grew his own powers, his fearful heritage. Across wide seas, in conquered cities, and among haunted mountains, the hunt took him. And as he drew closer to his objective, the clearer became the way she must be slain, the more certain his ability to sunder all her witchcraft and ancient science to rid the world once and for all of his creator – the white witch from the volcano.