From MangaHelpers:
In this world, there are those who look like humans but are actually beings with supernatural power. In order to respond to crimes committed by these kinds of people, an organization that employs some of their number has been established. Kurohimeyama Eve is a member of this organization, and she is also a teenage girl that has "Oni" powers. One day, she goes to meet a new member, Ichizuka Senya, who is a boy with dangerous shadow powers and a bad personality. In front of the other girls in the organization, though, he seems to act perfectly nice. What's even worse, he's transferred into her private religious school! Kurohimeyama's once-peaceful life will never be the same.