Shapeshifter is a blanket term for a variety of creatures or people who can change their form. These include the Skraeling Skinwalkers, Lycanthropes, and even the Dragon Emperor of China.
Lycanthropes, or more commonly, Werewolves originated as a species in the early 1800s. Two Greek magical researchers, Lucas Tselios and Ambrose Michelakos, were in the frontier of Charlesiane researching reports of abilities amongst some of the indigenous Skraeling population to change into animal form. In an experiement attempting to recreate this phenomenon using traditional european magical theories both researchers were altered to which they transformed into a human-wolf hybrids according to the phases of the moon. The tie to the moon phases were due to the rituals performed attempting to recreate the Skinwalker phenomenon. Believing the experiment to be a failure Michelakos returned to Greece while Tselios travelled to London to meet with other magical scholars.