Waga Tousou: Imouto no Tame nara Sekai o Shukusei Shite mo Ii yo ne!
わが闘争 妹のためなら世界を粛清してもいいよね!
A member of the Space-Time Vanguard Unit, Mina, travels from the future to warn Ichikawa about the consequences of his feelings for his younger sister. She attempts to dissuade him through various means, including persuasion and seduction, to prevent the future she foresees.