The Secret Texts — Holly Lisle

A magical war challenges the ingenuity of even the bravest of heroes in this thrilling saga of destruction, devastation, and disaster.
When Hardin fails to destroy this new threat, the Calimekkans bring back the few surviving Wolves who know the magic of the dark path. They offer endless sacrifices from their own people in a vain attempt to ward off the approaching evil.
Meanwhile, protagonists Kait and Ry are on the run, trying to figure out a way to create a new Mirror of the Dead that will contain Luercas permanently. Luercas has figured out that Kait and Ry are his main obstacle and begins to seek them out to destroy them. Their only hope is to lure Luercas in and trap him in another Mirror of the Dead -- before he destroys them along with all of Ibera.