Ep. 1: Basara meets his new demon sisters and reveals his hero heritage to protect them.
Basara Toujou and his father Jin await Basara's new sisters from Jin's remarriage. Basara meets Mio Naruse in a restroom, and she and her sister Maria are introduced as his new little sisters. The next day, Maria places an incest-themed video game in Basara's bed. After Basara saves Mio from thugs, she thanks him as her older brother. When Jin leaves for overseas, Maria and Mio order Basara out of the house, revealing themselves as demons with Mio as the Demon Lord heir. Basara reveals he is from the hero clan and drives them away. Jin informs Basara that Maria is in danger from the current demon lord's plot to steal her strength inherited from her late father, Wilbert. Maria and Mio fight evil forces until Maria is thrown off a ledge. Basara saves Maria from falling and shows a family photograph, stating he returned for his family.
Episodes
- Ep. 1 · Basara meets his new demon sisters and reveals his hero heritage to protect them.
- Ep. 2 · Basara and Mio form a magical pact while Yuki Nonaka returns to school
- Ep. 3 · Basara explains Mio's past to Yuki while demons attack the school during a blackout.
- Ep. 4 · Basara and Yahiro form a truce after the stranger attacks, revealing Zolgear as the culprit behind Mio's parents' death.
- Ep. 5 · Basara navigates morning encounters and learns of a curse while Yahiro meets reinforcements.