Maria Naruse

成瀬 万理亜

BWH: 64-48-65 Maria is Mio's sister and guardian. She will protect Mio no matter what. She is a rather childish person and likes teasing people no matter how serious the situation is. Despite this, she can be dead serious as seen when she revealed her real identity to Basara. (Source: Shinmai Maou no Testament Wikia)