Lycanthropy

Lycanthropy is a magical affliction which turns people into monstrous beasts. Though some lycans are good, most are violent and animalistic. Werewolves, werebears, weretigers, weresharks, werecrocs, wereboars, wererats, and wereravens are all kinds of lycans.
In casual speech, lycanthropy is often called a curse or a disease. In truth, the affliction is much more complicated than either. Paladins and other individuals normally immune to disease, for example, are still susceptible to lycanthropy. It is known that lycanthropy can only affect the living, so vampires and other undead cannot be affected by it.
There currently exists no known cure for lycanthropy once the affliction has become "mature". Magic which can remove curses can remove lycanthropy, but only before a lycan's first transformation (usually the next full moon). Thereafter, the affliction has bonded itself to the victim, and conventional magics cannot remove it. One also does not need to actually see the full moon in order to transform, so traveling underground does nothing to save a lycan from their transformation. Once the moon has fully crested the horizon, the affliction will take hold.
Haven Hill is a town located far to the north where willing lycans are allowed to live away from civilization.