Shifter
A long time ago a group of fleshformers mastered the art of turning themselves into various types of animals, over a prolonged period of using this magic it became almost second nature and when they interbred with humans they created the shifters, humans which can turn back and forth between human and animal form.
Today shifter genes are erratic like other supernatural genes. Usually activating only once every three of four generations. The chances of any of your direct family also being active shifter is astronomically small, but it possible for a grandparent or great grandparent to be. There's also a decent chance that twins, both fraternal and identical will share the trait if one has it.
Shifters can be either latent, or active.
Latents are effectively entirely human, but there is a chance that at some point in their adult lift the latent genes will activate and they will become either active or passive.
Active shifters are just like humans but often stronger and tougher, and most importantly have the ability to change into an alternate form.
The types of active shifters are known colloquially as fliers, runners, fighters and swimmers.
Fliers are shifters who can transform into anything that flies, usually birds.
Runners are shifters who transform into an animal that moves particularly fast, such as large cats.
Fighters are shifters who transform into an animal that fights very well, such as bears.
Swimmers are shifters who transform into an aquatic animal such as fish.