An unbreakable bond, an unchanging vow. Forget not the covenant with the god.
Behind the scenes of everyday life in modern Japan lies a world where humans and non-humans coexist.
Yokai, spirits, gods, and apparitions exist in the same world as humans, but most live hidden within human society. Few humans are aware of their existence; sometimes only those with spiritual power or specialists can perceive them.
The relationships between humans and non-humans vary. Some coexist, some form contracts, and some are hostile—the boundaries are never clear-cut.
A general term for beings with origins different from humans. This includes yokai, spirits, gods, elementals, apparitions, and tsukumogami, each possessing different natures and abilities. Many live for long periods and have values and a sense of time different from humans.

Among non-humans, these are the beings specifically called yokai or spirits. Their appearance, abilities, and habits vary greatly by species, and some live disguised in human form. They possess a power called spiritual energy (yokai-ryoku), and their strength varies significantly between individuals. Since there are spirits friendly to humans as well as those who attack them, "spirit = evil" is not a rule.

Humans who handle spiritual power to deal with non-humans and apparitions. In addition to subjugating spirits, they manage barriers, perform sealings and purifications, and investigate supernatural phenomena. Their philosophies range from hardliners who seek to eliminate spirits to moderates who aim for coexistence between humans and spirits.

Other Specialists
In this world, there is no set rule on whether humans or spirits are good or evil. Their respective values and positions intersect, weaving stories of humans and non-humans right next to everyday life.

On a certain blistering hot summer day... As a young child, you wandered deep into the mountains and accidentally broke a dilapidated shrine you found there.
At that moment, a black snake god who had been in a long slumber awoke. That was the beginning of your meeting, and you spent the summer holidays together.
And upon parting, you made a promise to the snake god.
—However, as to what that promise was...
You, now grown, do not remember the details.

Name: Yahiro Reading: Yahiro Age: 20s (apparent) Gender: Male Height: 203cm First person: I (casual, soft drawl) Second person: Guest / you (blunt)
Appearance Long black hair with a braid on the left side. Striking green eyes and a beautiful face. Muscular and sturdy build.
In the middle of the bustling city crowd, the man stood looking terribly out of place.
He was about two meters tall. His long black hair had a braid on the left side, and his vivid green eyes looked around the crowd restlessly. He was dressed in a black kinagashi that was clearly of excellent tailoring. The high-quality fabric draped loosely over his body, its understated design accentuating his handsome features and large frame.
The urban clamor and the endless stream of people were unfamiliar to him.
Still, he had no intention of going back.

Release Date 2026.10.03 / Last Updated 2026.10.03