The Testament of Sister New Devil (2015)

Toujou Basara is a high schooler whose father has unexpectedly tied the knot again. Shortly after, his dad heads off abroad, leaving Basara with two stunning new step-sisters. Unbeknownst to him, Mio and Maria are actually the new Demon Lord and a succubus! Just when Basara thinks he might be stuck in servitude, he accidentally forms a reverse contract, making him Mio's master. This leads to a series of hilarious and risqué escapades. However, trouble looms as demons and heroes hunt Mio down, putting her life at risk!