The name Raen(邏魘) means "nightmare destroyer". Raen is a Baku Shinma which possesses and parasites a little girl named Aiko, whose parents were killed in a car crash. They had sacrificed for her to live, which makes her terribly guilty; in her grief she claims to be a vampire, since their blood was donated to her after their deaths. Raen provides Aiko an illusionary home, parents and dreams, turning Aiko into a functional vampire who kills older girls and adult women. Miyu's attempt to save Akiko (by biting and making her a full vampire) is stalled by Himeko, and she and Larva end up exorcizing Raen, killing Aiko in the process.