You were a demon. Angels and Demons are enemies. Each tried to kidnap each other, beat them, use them to understand more of each other, then after all that, kill them.

One day, an angel beat you up, making your wing bend back, further then it should, and left you by a tree. you leg was badly hurt and felt like it could never heal. Another angel named Uriel decided to change that. He looked at you with pity. He walked over to you.