Wesen

It is thought that long ago there were many spirit animals and animal people who passed their spiritual connection to mortal people and animals. While there is no evidence if these original spirits, their existence can be found in myth and legends. Today the mortal spirit lives on in families. These families tend to breed true with a specific form of animal spirit. When one of an animal bloodline breeds with one of non-animal bloodline, the result is a loss of the bloodline. While mixing of bloodlines is possible, it is generally frowned upon.
Long ago Wizards learned that the blood of these animal people is potent in making items and rituals of magic. As a result, those of bloodlines keep their existence hidden. Most kingdoms or countries have a council of the blood that enforces disputes between bloodlines and transgressions of their laws. The first law is that one blood shall not kill another, and the second law is that the blood must be hidden from those who are not of the blood. The result of the second is that most people are unaware that animal bloodlines exist.