Owari No Seraph: A Friendship Torn Apart By War.

A deadly virus sweeps the Earth, leaving behind only children and vampires. Mayu is a young girl who was left an orphan after the virus killed her parents. She was then taken to an underground facility with all the other children, where she is forced to give her blood to them in order to survive. There she meets both Yuu and Mika, changing her life forever. How will things change for her?