Snakeroot by Andrea Cremer. Bosque Mar haunts Adne and Logan's dreams, trying to turn Adne to the dark side as he attempts to escape the Nether, where Calla, Shay and the other Guardians trapped him in the final battle of the War of All Against All.
Nightshade (Nightshade, Calla is the alpha female of a shape-shifting wolf pack. She is destined to marry Ren Laroche, the pack's alpha male. But then, Calla saves a beautiful human boy, who captures her heart.