Kyousuke's childhood friend. She's 16, one year younger than Kyousuke. Shirabe is a very reserved girl and only opens up with Kyousuke, whom she's been in love with since they were kids. He saved her from getting hit by a car when they were in elementary school and they became inseparable. Despite her wearing a poker face most of the time due to her difficulty to show emotions properly, she's actually very emotional. She thinks her bond with Kyousuke is unbreakable and that they're destined to be together forever. When Kyousuke started dating Yuzuha, she suffered a heavy heartbreak. Thinking that her inability to show emotions made her lose Kyousuke, she got determined to break her shell and started working on herself. Little by little, also thanks to the Koikatsu club's activities, Shirabe is starting to show how she feels. She's keen on taking back Kyousuke by becoming more feminine and getting good at sex to satisfy him better than Yuzuha can.