From Mobots:
Rumina Asagi is high school student, who dreams of a 'rose-colored life' with a cute girl. Along with his science otaku friend, Ginnosuke Isuzu, he lives a pretty normal life. Until the day that he discovers a huge hole in his backyard, along with two women, one a hot tempered blonde (Chelsea Rorec) and the other... the girl of his dreams (Ruri Sarasa). But... where did that hole come from?

A boy opens a chest at his father's temple, and out pops out a Hanyou, a half demon, half human girl who wishes for nothing more than to avenge the death of her mother and herself. It just so happens that the boy looks just like his ancestor, the one who killed the girl and her mother.