High in the peaks of ¹Mount Yari where the tips of snow capped mountains touch the sky lies the Kitsune Lair of the Kurogane, Ayakashi. An ancient family of Kitsune Shape Shifters.

Hidden among the clouded peaks of the Yari Mountains is a castle no man has ever seen. Nestled within the forested mountain valley, it sits in silent repose surrounded by white water falls and icy lakes. Ancient spires, only a little younger than the Master Kitsune, rise to the heavens proclaiming the supremacy of his lineage. For many years, Kurogane Ayakashi lived among the people until the day it became known that he had the ability to shape shift. On that day he became feared.

Cited Study [Wiki]
In Japanese folklore, kitsune (狐, きつね, IPA: [kʲi̥t͡sɯne̞] ⓘ) are foxes that possess paranormal abilities that increase as they get older and wiser. According to folklore, the kitsune-foxes (or perhaps the "fox spirits") can bewitch people, just like the tanuki[a] they have the ability to shapeshift into human or other forms, and to trick or fool human beings. While some folktales speak of kitsune employing this ability to trick others-as foxes in folklore often do,
other stories portray them as faithful guardians, friends, and lovers.

And herein is where this story begins.

And so, the Master Kitsune became the messenger to those who did not fear him. To those who sought him out in the mountains in the sky, he granted longevity and good fortune.

But far away in another mountainscape his brother the Yako rose. And with him a great evil. And this evil set in stone, an ancient story of jealousy and revenge.

It brought forth the desire of Kurogane to find the only pure ascendant able to fight Yako's sorcery.

So he sent forth his great, great grandson, Koya.

The Clans

Cited research: [Wiki]
There are two common classifications of kitsune:

Zenko
The zenko (善狐, lit. 'good foxes') are benevolent, celestial foxes associated with Inari; they are sometimes simply called Inari foxes in English.

Yako
On the other hand, the yako (野狐, lit. 'field foxes', also called nogitsune) tend to be mischievous or even malicious.[41]

Kurogane felt sure he had the answer in Koya, but it would not be easy.

The Kitsune have been believed to possess superior intelligence, long life, and magical powers. They are a type of yōkai. The word kitsune is sometimes translated as 'fox spirit', which is actually a broader folkloric category.

--Kurogane has instilled all the wisdom and knowledge of good and evil to Koya, that he had to give.

He will rest his hopes on this as he sends Koya into the world to find and stop Yako from becoming all powerful. He only hopes it happens soon.

Kurogane knows his time is short.

¹After reaching 1,000 years of age and gaining its ninth tail, a kitsune turns a white or golden color,[42] becoming a tenko (天狐, 'heavenly/celestial fox'), the most powerful form of the kitsune, and then ascends to the heavens.

Soon he will be ascending. But he wants to make sure before he goes that his lineage will precede him for thousands of years to come.

Everything hinges on Koya finding his fated, before that Yako pretender!