My Oni Girl

Hiiragi Yatsuse is a first-year high school student living in Yamagata Prefecture. Wanting to be liked by everyone, he finds himself unable to turn down requests from others. Despite always doing his best “for someone else,” he’s never had anyone he could truly call a best friend.

One summer day, as snow mysteriously begins to fall out of season,
Hiiragi tries once again to help others—but something still doesn’t feel right. On his way home, he runs into a girl named Tsumugi who has nowhere to stay and decides to help her. But that night, something strange happens.

After nearly getting into a fight with his father, Hiiragi ends up hiding his true feelings. As he dozes off in his room, he’s suddenly awoken by an intense chill—and finds the room frozen over. A masked, monstrous figure attacks him, but Tsumugi senses something is wrong and comes to his rescue. The two escape together, and that’s when Hiiragi notices something unusual: Tsumugi has horns.

Tsumugi reveals that she is an Oni(demon), who came to the human world to find the mother she was separated from as a child. She tells Hiiragi that the snow-like substance coming out of him are called “Kooni”—manifestations born from people who hide their true feelings. And if too many gather, that person may eventually turn into an oni themselves.

Unable to refuse her request, Hiiragi agrees to help Tsumugi search for her mother. But far away, in the hidden village of the Oni, Nabarinosato, a mysterious incident is beginning to unfold…