Ake no Emblem

A series of murders occurs in the area where Runa lives, with each victim being an 18-year-old woman whose blood has been completely drained. Each of them has a scar or birthmark resembling a crescent moon. One of Runa's friends, who also has such a mark, becomes a victim. After Runa escapes from the killer following a confrontation, her existing headaches intensify, and a red crescent moon mark appears on her forehead. Subsequent events begin to revolve around her.