When the Gods Slept — Allan Cole

King of Kings, Lord over Men and Demons Alike: Only one ruler had ever held that title, and now Iraj Protarus, an orphaned prince exiled to a small village high in the Valley of the Clouds, dreamed of being the next great conqueror. The key to his destiny would be Safar Timura, a youth with an awesome gift for sorcery, whose visions foretold Iraj's rise to power. And in those visions, Safar stood at Iraj's side, his soul-blasting spells enabling his friend to attain his dreams. But Safar had other visions with darker portents, and his spellbound knowledge raised secrets better left buried. The road the two men followed would be rich in titles and fortunes, but it would also be rich in death and disaster, in intrigue--and in unforgivable betrayal ...