The Testament of Sister New Devil(Shinmai Maou no Testament) is a sexually Charged Mature anime. The anime takes place in a world where demons are real, and Basara Toujou--Son of the famous Jin Toujou, he has to protect his two demonic step-sisters(Mio and Maria Naruse). He forms a Master-Servant contract, where they perform... Sexualized acts to increase their overall demonic/magical power.