I don't know about you pink things, but for trolls relationship drama can get really violent really fast. Self-discipline's a virtue but not everyone can maintain that all the time, which is where I come in. A Threshecutioner's job is to make sure society runs smoothly and there aren't any really major disruptions to people's daily lives. Keeping the world oiled, that kind of thing.

The undead and the monsters are the same general idea. They're a disruption in society and they mess up the works, so kids in need can put out a call to us whitecoats to remove their problem.

[ Basically, picture someone made a whole branch of social enforcement modeled on the Sassy Gay Friend and gave them weapons. ]