Angel Fire East by Terry Brooks - USED

As a Knight of the Word, John Ross has struggled against the tireless dark forces of the Void for twenty-five years. Ross is driven by dreams that show the world reduced to blood and ashes by the Void and its minions. But for all his power, John Ross is only one man, while the demons he battles are legion.

Then Ross learns of the birth of a rare and dangerous creature formed from the very essence of wild magics. If he can discover its secret, the creature will be an invaluable weapon against the Void. But the Void also knows its value, and will not rest until the creature has been corrupted - or destroyed.

Desperate, Ross turns to Nest Freemark, a young woman with magical abilities of her own. And there they prepare to face an evil more ancient and powerful than anything they have ever encountered.