Saya

"Saya" is the name given to an extradimensional alien brought into this world the experiments of a Dr. Ougai, a Japanese doctor working for the Tokyo University Hospital. Saya initially lived with Ougai, until she got loose in the hospital, feeding on cats, and eventually human infants. "Saya" met Fuminori Sakisaka in the hospital, who, because of brain damage from an accident, saw "Saya" as a normal girl, buy saw everyone else as horrific monsters and everything as covered in blood and gore. Fuminori fell in love with Saya, and under her influence, discovered a taste for human flesh. Saya and Fuminori go onto kill several people including their neighbors and one of Fuminori's friends.