A Kitsunejin is a person with the ability to become a fox. This is a natural ability, but usually must be taught to small children before they are able to transform on their own. They have several tails in both fox and human forms; Inu-Kitsune has six.
Kitsunejin generally have magical abilities, especially illusionary and deceptive magic, as well as more advanced physical senses than Humans, at least in humanoid form. While they can't get as much information from their noses as Lupa or Mongoosetigers, they can differentiate between species and obvious hormonal/pheromone changes.
Known Kitsunejin characters in Suburban Senshi include most of the Amestris-Langister family.
Hudra are a similar species by appearance but has no known relation to Kitsunejin.