Translation: sky fox
Alternate names: Inari kūko
Habitat: the sky
Diet: none; they have no physical bodies and do not require sustenance
Appearance: Kūko are zenko, or good kitsune, which have lived for an extremely long time and achieved the highest ranks of kitsune society. A tenko can become a kūko after reaching three thousand years of age. Upon achieving this rank, a kitsune takes on a much more human-like appearance. They lose their tails entirely, although their ears still resemble a fox’s. They do not have physical bodies, and exist as being of pure spirit. They are telepathic and clairvoyant, and can even see into the future. Their level of magical power is the highest it will ever be: on par with the gods.
Behavior: Although they are the oldest and most powerful form of kitsune, kūko are only the second-highest ranking kitsune, after tenko. This is because after three thousand years they have reached a sort of retirement age where they are no longer working in the service of Inari—whereas younger kitsune still actively serve the gods. A kūko’s duties are more like that of a privy council member or a venerated elder.
Interactions: When kūko interact with human beings, it is only to do good deeds. They might increase the prosperity of a temple or a household. They might help a good and honest person achieve fame for their skills. And they might possess a pure-hearted but foolish person in order to teach him how to improve his life. When a kūko possesses a human, it does not cause mental disorder or sickness in the way that is commonly associated with kitsune tsuki.
Legends: A late Edo Period book called Kyūsensha manpitsu tells the story of an encounter with a kūko.
A kūko who had been living in Kyōto for a long time decided to make a journey to Edo. Along the way, he stopped to rest at the house of a samurai named Nagasaki Genjirō. He decided to “borrow” the body of one of Genjirō’s servants—a fourteen year old boy. He spoke through the boy and described to Genjirō the different ranks of kitsune and the differences between zenko and yako—good and bad kitsune. He explained that while yako harm humans, zenko possess stubborn or foolish humans in order to teach them important lessons, and they only use their magic to help people. He explained that he was in fact a zenko, merely inhabiting the boy’s body temporarily.
The kūko remained in control of Genjirō’s servant’s body for five days. During this time, he entertained Genjirō’s household and neighbors with tales of the Genpei War, the Battle of Dannoura, and the Battle of Sekigahara. After everyone had been thoroughly entertained, the kūko departed the servant’s body—but not before he used his magic to cure the diseases and ailments the boy had been suffering from.
Before he left, as a gesture of thanks for Genjirō’s hospitality, the kūko left presented Genjirō with a signed calligraphic scroll containing the secret inner teachings of Hakke Shinto.