That's sort of what I was looking for.
Well, he's a short summary I suppose.
Toen's parents were killed because they created Toen, a mix of god and demon. He strives his whole life to kill the woman that killed his parents, but in the end, he changes and finds that it is best to grow up and except the deaths of his parents. From there, he becomes the muderers right hand man. He gets married, has a kid and everything's going great... until Sozosha, the muderer basicly tells him that he has to die to make room for a new god.
She puts a curse on him that will basicaly eat his internal organs so that there is no real way to tell outwardly that he's dying.