Rebel, the Shattered World Saga, Book 2 — Dennis K. Hausker

Aron's peaceful life on his father's farm ended abruptly and he struggled with galling captivity in the palace while he formed a fearsome corps of expert fighters. They managed to escape fleeing into the wilds but their new life is tenuous with daily challenges merely to survive. His problems seem to mount on a daily basis with his personal struggles with the significant women in his life, the barbaric savages living in the wilds, and then the shocking discovery that threatens the world with a nightmare resurrected. Their limited understanding of their whole world has left them vulnerable. Can Aron and the allies rise to meet the challenge? They don't know the answer to that question, and they fear the worst under the circumstances.