Native to Japan, a kitsune's true shape is a fox, but they can also shift into human form, so they are monitored by the SuperNatural Agency for Mostly Human Protection (SNAMHP). they are very diffcult to catch because a full-grown kitsune can often read minds, see the future, fly, possess people, and create illusions that mimic reality. A clever Tracker might spot one by its fox-shaped shadow. Dogs are sometimes useful for tracking them as a dog can sniff out a kitsune's true nature.
The only kitsune mentioned in the book is Keiko Kahn.