The Daemons Are Calling

The story follows the captain of an elite unit of foot soldiers fighting on the front lines against a demon army. After losing everything in the battle the captain is saved by a powerful demon who is one of the "Four Horsemen" a group of 4 ultra powerful demons that defected from the demon lord's army to defend the humans. How will the captain move on after losing everything, and will he prove himself to the Horseman that saved his life?