Fortress of Dragons - C. J. Cherryh

Shadows from another realm threaten the world with eternal darkness as this "stunning high-fantasy series" continues (Denver Post).

An ancient war between shadowy Immortals persists to this day, thanks to the wizard Mauryl and the Shaping he conjured to face the Shadows of Chaos. Both more and less than human, Tristen is that Shaping. And his victories have won his friend Cefwyn both a kingdom and true love.

But the Lines that hold the world in place are shifting again. A ruthless enemy is preparing for battle. Once again, Tristen will take up the sword inscribed with "Truth" and "Illusion" on its blade. But he faces more than a pretender to Cefwyn's throne. The Shadows he sees are straight from Ruin—a flow of darkness covering the world like ink . . .