Totsukuni no Shoujo

In a world split between two realms, its habitants were told never to cross to the other side, lest they be cursed. A little girl from the inner land named Shiva and a demon from the outer land simply known as “Teacher” initiate a quiet coexistence on the same side of the forest. But when Shiva leaves Teacher’s care to seek out her grandmother, their secret comes to light. (Source: Crunchyroll) Note: Originally released as a movie-length OVA. As streaming on Crunchyroll, it is split into 3 ‘normal’ length episodes.