There was a character, from a kind of underground comic book series...
Anyway, the young man is called "Saint Sinner." He is a young man, perhaps in his early twenties, who comes to be possessed by both a demon and an angel simultaneously.
This dual possession gives him an interesting power: He can 'evolve' or 'devolve' any form of biological life he puts his hands on. If I remember correctly, he also possesses a special coat that allows him to travel between dimensions.
I always thought the Saint Sinner was pretty cool.