Trolls are solitary hunters, for their wickedness is anathema even to other giants. They occasionally roam in small gangs of two to four, but only when prey is plentiful or a particularly strong counterforce has broached their hunting grounds. In rare instances, an old and powerful troll comes to lead small tribes of trolls. Such "troll kings" possess enough cunning to lead their hordes in devastating raids and massacres, and their presence permanently alters the surrounding ecosystem. A wide variety of trolls exist, from the terrible monster traditionally associated with the name to the water-dwelling scrag and hybrid flood troll. Regional variations exist as well-mountain trolls among stony peaks, for instance, or moss trolls in swampy bayous-but all share the same trademark regenerative powers and insatiable thirst for blood.