Peril's Gate — Janny Wurts

On the world of Athera, the fate of all realms hangs on the resolution of the brutal conflict born of prince against prince. Branded a minion of evil -- escaping the death sentence imposed by his half-brother Lysaer and his Alliance of Light -- Arithon, Master of Shadow, now faces the last choice remaining to him in the merciless winter wilds: to cast his lot with a renegade enchanter whom Arithon dares not trust ... or die by the swords of fanatical enemies.