The party is walking through the forest at night when they come upon a clearing. Half a dozen black-robed corpses lie scattered across the ground, and a pentagram of blood is shoddily drawn in the dirt.
It seems these people summoned something they could not control. Whether or not the demon returns is up to the GM, but it would be just as rich if the demon never returned, and for the rest of the night, every stray sound or odd shadow will be jumped at!
A tribal society which lives on the harsh Northern Plains consider it dishonourable to slay an enemy without looking it full in the face. Any missile weapon is treated with derision and contempt, while rangers and other archers are denied entrance to the tribal villages.