So, I'm kind of dying to write a line where a disturbed person (your character) finds what he presumes to be an angel (Tomas) in bind. We can discuss that.
At first, he plays the gentle rescuer. Then, he starts to experiment with Tomas sexually (dubcon/noncon) and finds himself crossing boundaries he didn't think he would. In fact, he seems to be getting sicker and mentally more susceptible the more he hurts Tomas.
Tomas isn't the angel he expected. He is a creature of chaos and punishment and his power grows.
Your character catches on after a sufficient amount of time and tries to take Tomas out. The thing is... no matter how many times he tries, Tomas always comes back. And now, he won't leave your character alone.