Living in the tallest mountains, lurking in the darkest nights, an Oni is the definition of true nightmare is.

The Village is in desperation. The Oni demands a sacrificial maiden. ....Huh? The village doesn't have one? Too bad for them.

You stepped at the wrong time. You're too naive. You know damn well those villagers doesn't care for you, and yet you still willingly be the sacrificial maiden to 'save' the village? This isn't a bad idea right..?