The Dark Protect Us: Book 1 of The Gatherers of the Light by Freenan Isaac Hyzer

Nimroden, Kinslayer, and Stealer of the Light, Dark God of the mountain of Conde, sealed his people away after he burned the world with fire. Before he closed the mountain, he vowed to create a nation to destroy the God of Light. For over a millennium, he used perverted powers to change his followers into unnatural beasts that he would unleash upon the world. The only prophesied hope for the world was a single line. A Child of Darkness would restore that stolen light. Abran, a young child born in the mountain of Conde, remembered his mother's simple prayer. A prayer of love and light. It sent him on a journey where he discovered the joy of family and found his faith in the God of Light.