Maria Kurenai

Maria Kurenai is a very distant relative of Shizuka Hio. She allows Shizuka to possess her body in exchange for being allowed to drink Shizukas blood which would strengthen her sickly body. Due to Shizukas untimely death this promise is never fulfilled. She seems to be fond of Ichiru hugging Zero when she mistakes him for Ichiru and asks Yuki to tell Zero that if he sees Ichiru to tell him Maria wants to see him again. Source: Wikipedia