The Testament of Sister New Devil
The Testament of Sister New Devil(Shinmai Maō no Tesutamento) is a Japanese light novel series written by Tetsuto Uesu and illustrated by Nekosuke Ōkuma. The story revolves around Basara Tōjō, a high school student studying at Hijirigasaka Academy. When his father Jin suddenly gets "remarried," He asks Basara if he wants to have sisters. Basara meets his two cute stepsisters, Mio Naruse and Maria Naruse. After his father departs overseas, Basara quickly finds that the two sisters are actually part of a demon clan.