Ships of Merior — Janny Wurts

As the prophecy foretold, the art of power over light and dark was channeled through two princes: And the fogs that had smothered Athera's skies were dispersed. But in defeat, the Mistwraith set its two royal captors at odds under a powerful curse of vengeance. Now, locked in deadly enmity, the princes- Lysaer, the Lord of Light, and Arithon, the Master of Shadow--hold the fates of nations and the balance of the world's mystical powers entangled in the throes of their blood feud.