Theresia

Theresia, most commonly known by her Japanese name Rea Himuro, is one of the main characters of Dies Irae, being one of the game's heroines. She is an upperclassman to Ren, Shirou and Kasumi, and one of the few people Ren manages to be friends with outside of his usual childhood friends. She lives in the church of the city, alongside its running nun Riza Brenner, who acts as her mother figure.