Unfortunate Son (en Inglés) - Curtis Yost

Michael never asked to lose his father. He never asked to share his soul with a demon, or to watch his father turn to ash in his very arms. But in a world where "The Sacred Timeline" is written in blood, Michael is the Unfortunate Son,a boy who inherited a war he isn't sure he wants to win.
Now, bound in Holy armor that burns his skin and suppresses his volatile power, Michael is cast into the Void,a surreal purgatory, where the sky bleeds red and the ground is built of fractured bone. Guided by Dawn, a girl who is as much a mystery as the abyss itself, Michael must journey to the Valley of the Fallen.
There, he must face a trial more agonizing than any training: reliving thirty-three years of a life he was forced to forget. As the line between Michael the boy and Larua the monster begins to dissolve, he must decide if he will follow the path laid out for him, or if he will burn the timeline to the ground to save what's left of his soul.