Shinmai Maou no Testament Burst

After protecting Mio and Maria from the enemies pursuing them, Basara Toujou tries to return with them to a quieter life, but the demon world does not allow that peace to last. Maria's older sister Rukia appears and demands that they travel to the demon realm, where Mio's position as daughter of the former Demon Lord remains the center of a dangerous political struggle.

Basara finds himself caught between factions that want to use Mio or eliminate her, while his master-servant contract with her continues complicating their feelings. With old enemies returning and stronger threats emerging, he can no longer protect only the household they created together; he must confront the system that made Mio a target in the first place.