The Demon Contractor

At the beginning of the universe, Light and Darkness existed. The two instantly took a dislike to each other due to their opposite nature. Light is the symbol of life, while Darkness is the symbol of death. Light established itself as the God of all living things, while Darkness became the Ruler of Death. Their creations fought each other for millenniums, and eventually, Light won and slain Darkness, but there was a side effect. As Darkness fell, his magic contaminated the lands and transformed many creatures into his own creations; Demons. Being the spawns of Darkness, they were naturally oppressed by their counterparts; humans—the children of Light, who had their progenitor's help. Yet—humans still envied and coveted the Demons' powers. Eventually, they found a way to use a Demon's powers—becoming a Contractor. Selling their soul to the Devil. If you started at the bottom, would you make the choice to become a Demon Contractor?