Dark Oak by Jacob Sannox

Humanity has finally defeated the Dark Lord, but Morrick fought on the wrong side. Though he was a slave, he is branded a traitor and must earn the trust of new lords in order to return to his family - if they are still alive… Now that their common enemy is dead, the nobles begin to forget old loyalties, and Queen Cathryn’s realm looks set to plunge into war once more. But there are older and more terrible powers dwelling within the forest, and when they are awakened, Morrick will decide who lives or dies.