“ The forests, the swamps, the lands lost to wilderness, fang, and willow. These lands are home to the creatures of wiing, tooth and claw. Some far more capable of fending off the hominids, others still, are less fortunate, falling prey to spears, arrows, and dogs. As the hominids encroach upon the sacred woodlands and miry bogs there are times that the thorns and vines are animated by the spirit of the land in order to fight. In this way the mysterious guardians are formed. In the shapes of wolves, bears, and many other greater and more terrible beasts, each with eyes of glowing emerald. Fiercely defending creatures of burrow and glade.”
“ <br />
The local band of 'nasties' (goblins / orcs / whatever) lives in relative peace with the local population.<br />
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.<br />
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).<br />
Next time the PCs are in the area they find themselves VERY unpopular with the townsfolk.”