Maria is the only daughter of a vampire couple aristocrats. It's a girl in gentle and cheerful, despite his serious health problems preventing him from leaving her house. She has family ties with Shizuka Hio, which uses it to reach Kaname Kuran, in effect, the body is weakened by Shizuka lack of human blood, it chooses to own one of Maria in order to camouflage among students in the night class of Cross Academy.
In exchange for what she offers her blood to Maria, the curing of any disease. After Shizuka left her body, Maria falls into a deep coma from which she wakes up only once every academy students went on vacation. Upon waking, she is delirious and takes Ichiru Zero, which it has committed. She then confesses that the real Zero responsible for killing his parents but Shizuka is not another person. However, she was offering the name. Just before returning to her family, she says she would like to see Ichiru and kindly to ask Zero to report this service.