Urban legend often portrays these as lycans or werewolves, but Wolfkin are something else. Their origins are unknown. Almost every culture speaks of creatures with kinships with animals, wolves in particular, and they are often portrayed as violent and dangerous.
In truth, not all wolfkin are mindless monsters. Indeed, wolfkin develop a relationship with wolves and some wolf-like characteristics in themselves. They can communicate telepathically with nearby wolves and will gradually develop golden eyes with very keen sight and hearing. In addition to an extraordinary sense of smell, they are able to discern other humans' and animals' emotions with considerable accuracy.
Those which delve too deeply into their telepathy may go mad and eventually believe they are a wolf themselves, behaving, eating, and living as a wolf (or in a pack) in the wild. These insane wolfkin are the likely sources of the werewolf legend, and are indeed, quite dangerous.