After ending the battle against Zolgia, Basara regains his peaceful life with his two little sisters, Mio, the daughter of the previous demon lord, and Maria, her little sister who's also a succubus. As Basara pursues the preparations for the sports festival at school, one day he's attacked by a person being manipulated by magic. Recalling the strange gaze he felt at school, a suspicion of his begins to grow...
Huh, I guess that's the Demon 
Lord's weapon for you, huh?
Oh, wie von der Waffe
des Dämonenkönigs zu erwarten.
Vaya, no está mal para 
el arma del Rey Demonio.
Vaya, nada mal para el arma del Rey Demonio.
Beh, non mi aspettavo niente di meno 
dall'arma del Signore dei Demoni.
Como esperado da arma 
do Lorde das Trevas, hein?
О, сразу видно — оружие Повелителя демонов.