The Testament of Sister New Devil

The Testament of Sister New Devil follows high school student Basara Toujou after Maria and Mio move into his home. Maria is a succubus, Mio is destined to become a Demon Lord, and Basara has his own hidden connection to a clan of demon-fighting heroes. A master-servant contract unexpectedly places Basara in charge of the two girls, forcing three very different supernatural backgrounds under one roof. Their growing bond becomes essential when outside threats arrive.