Engel appears to be an emaciated, youngish man. He’s so covered with old scars, burns, cuts, and open wounds that it’s hard to tell anything more than that. His hair is dead white, although he’s usually missing chunks of it at a time, leaving his scalp a bleeding mess. His eye sockets are empty, scarred holes that he doesn’t bother to hide.
Most demons are interested in tormenting mortals, either for power’s sake, or for their own personal amusement. They are highly dangerous, and should be dealt with rarely, if at all. However, Engel is not a typical demon. He is interested in torment and suffering in a completely different sense.
Engel is an agony demon, and the ultimate masochist. He craves sensation, and all he can feel any more is pain. It is his greatest pleasure; more than that, it’s something he feeds on.
He gravitates to places where it is likely that he can feed his addiction: prisons, madhouses, the torture chambers of despotic tyrants, any place where he might find people to accomodate him.
Usually, he is seen as just another prisoner, and people seldom pay him any mind. However, his almost puppy-dog eagerness to succumb to any concievable torture tends to unnerve even the most sadistic warden, and his tendency to try to take punishments for his fellow prisoners ceases to be heroic very quickly and becomes highly disturbing.
While he is not interested in anything that happens to others, his presence sometimes exacerbates conditions, driving wardens and keepers to greater depths of depravity as they try to get a reaction from him that makes sense. Given the general mentality and temperment of the sadists Engel seeks out, they do not generally confine their newfound exhuberence to him.
Of course, there’s always some so-called hero that comes and throws open whatever place Engel has found, slaying the keepers, and releasing the prisoners. Of course, this necessarily means they misguidedly release Engel as well, and he has to start all over again.
Engel usually pays no mind to anything that happens beyond his sole interest of absorbing as much pain as he can. He can speak, he just doesn’t. If anyone tries to start a conversation with him, he is unlikely to pay the slightest bit of heed. If he angers someone enough that they threaten him or actually strike him, he will keep doing whatever it is that’s making them mad, specifically so that they will inflict harm on him.
If he cannot find someone to fulfil his masochistic addiction, he will inflict injuries on himself of varying severity. He doesn’t know much about anatomy, and if he were a normal mortal, many of his self-inflicted injuries would be fatal. However, he is a demon, and more than that, an agony demon, and a little thing like physical injury won’t kill him.
While he seeks out people with sadistic tendencies, Engel will avoid true sadists when possible. In fact, true sadists are among his least favorite people in the world, worse than even the heroes that try to "rescue" him. Experience with his brother Oni has taught him that people won’t touch him, specifically because *not* torturing him is the worst they could ever do to him, and they know it.
Engel is not likely to be a threat to any PCs, unless he’s trying to provoke them into attacking him, and even then he’s more interested in lingering injuries rather than anything he’s likely to recieve from PC hands.
It’s entirely possible that in the course of their heroic duties, the PCs might fing Engel in the dungeon of whatever madman they’re currently overthrowing. He will almost certainly look like he requires immediate medical attention, and will also NOT want said attention. That should thoroughly disturb most characters.