Kasen Ibaraki is a hermit who lives inside her Senkai, located on the Youkai Mountain. There are rumors that she is an oni, but the truth remains shrouded in mystery.

Hermits are humans who have attained super-human abilities through training. Many have long lifespans, few worldly desires, and only eat the bare minimum amount of food necessary to survive. Kasen, on the other hand, loves food and alcohol. That alone is probably enough to set her apart from most hermits.

A Senkai is a special space created by a hermit. The space reflects the creator's will. Kasen mentioned that the space could be created by using hermit philosophy. Although Senkai aren't separated from the real world, they are cleverly hidden. Some Senkai can only be reached by following the correct path.

Kasen, much like other hermits, created her own Senkai on the Youkai Mountain and built her mansion there. Kasen's Senkai has mountains that look like they came out of an ink wash painting, and the climate is calm. Even though it is located on the Youkai Mountain, her Senkai's environment is very different from everywhere else on the mountain. It is obvious that Kasen has adjusted it to her preference.

Imagine a private space separated from outside information, noises, and calamities. The shape and form of this space can also be modified however you please. If such a space existed, its value would be immeasurable. What would you do if you found such a place along with the way to obtain it? You should probably reconsider because the hermit's path is extremely harsh and unforgiving.