"Her Curse isn't forgiven easily, but some of us have found our own little mercy." From Ways of the Cursefolk, by Aarin Bloodskin.
Skinwalkers are one of the Cursefolk, descended from people cursed long ago. Skinwalkers know their own story, and how they came to be. Those who displease the Wolf Mother Lupa, especially those who spurn her gifts or lack any self-control, are cursed as Lycanthropes.
Skinswalkers are descended from clans of Lycanthropes who found a cure to their condition, of sorts. Each clan has its own tale of how or why it found mercy, but none found it at the hands of Lupa herself. The first skinwalker was a Witchwolf Paladin of the Summer Rose. It was the Summer Rose, or so some say, whose tears rent back the curse. It didn't take the stain completely away, but borne something new from it.
However they came to be, Skinwalkers tend to breed true amongst their own kind. Sometimes they pass their condition on to human or other kinds of mates, but the gods are merciful to a few and spare them of it. Skinwalkers, much like Dhampir or Tieflings, try to hide their condition if they can. Pretending to be human instead of some beast-folk keeps them from facing persecution in areas that Lycanthropes ravage.
Its important to note that each Skinwalker's opinion on Lupa and Lycanthropes varies. Sometimes a known Lycanthrope becomes a Skinwalker, other times a Skinwalker is revealed to have been a Lycanthrope in secret all the while. Skinwalkers have become paranoid by nature, preferring to hide their natures out of practicality instead of risking any trouble it might otherwise bring.
Crux: Lycanthropes have long dwelled on the outskirts and underneath the streets of Crux. Gangs of Wererats and Werebats feud in the sewers, while a pack of known Halfling Werewolves secretly protect the Wolf Quarter. Skinwalkers fall into all walks of life, most often coming from smaller communities to work within Crux, from Ainesia or the rest of Ith.
There are three Clans of Skinwalkers that have made their home in Crux. One of them is fused tightly with the Church of the Summer Rose, nicknamed the Summer Wolves by those who've heard of them. All three of these Clans have a large families, both human and skinwalker.
Within Crux itself, Lycanthropy itself is outlawed. Skinwalkers are lumped into this category, with most Cruxite Courts regarding no difference between the two. As such, Skinwalkers keep quiet on their bestial natures and try to hide it. A few find exceptions to this rule, becoming "Licensed Lycanthropes", but this License is based on a byzantine, loose connection of ancient and modern laws.