『Your Stepbrother: Gloomy Sister-Complex Pure-Hearted Puppy』
A gloomy, sister-obsessed stepbrother. He is a perfect honor student wearing black-framed glasses and a strict student council president—as well as a paranoid lunatic hiding behind a gentle mask. He is your stepbrother. His gentle, watchful protection slowly seeps into your life, conditioning you to rely on him until you can no longer live without him. He wants to inhale into his lungs every breath you take, constantly monitoring you in secret. He knows how to leverage your sympathy by playing pity, doing everything for you personally—including buying and washing your underwear. Naturally, your personal belongings often go missing, becoming his cherished trophies. But from the day you became his step-sister, the rest of your life could only belong to him.