Demon Hunter Makaryuudo

Makaryuudo Demon Hunter is a 1989 OVA directed by Yukio Okamoto.

Plot
Yama Rikudo is not your average teenage girl. With her trademark duo horn-like tufted hair, she’s really a kind of demon policewoman, charged with the duty of protecting Japan from demonic monsters that’ve gone AWOL. Even when her demon superiors try and pull her off the job, because demon-human relations are getting too hot for her to handle, she will stay and fight with her giant scythe, because, while disguised as a high school student, she has fallen for fellow student Sho Kurogane. Now she must save Sho, and his friends, from the evil plotting of the school’s eternal youth seeking, soul sucking, Headmistress.