Operating out of Armudstadt, the notorious city of corruption and deceit and centre of the Kingdom of Dernwich, the Duchampe Society takes its name from its founding father, one Vergrin Duchampe, who lived around the 18th century. Duchampe, an Elvish merchantman - or rather, a leader and “godfather” of a great deal of lower Elvish merchantmen, was notorious for his skill at wagers.
The local band of 'nasties' (goblins / orcs / whatever) lives in relative peace with the local population.
Along come the PCs and go through their usual heroic monster bashing routine, wiping out the nasties and pinching all their stuff, then continue on their way.
Problem is, they don't kill ALL he nasties. The survivors want revenge and, after spending a few months recovering, start to take it in their own inimitable style (which is not unlike that of the PCs come to think of it).
Next time the PCs are in the area they find themselves VERY unpopular with the townsfolk.