At the onset of Fuuka's second year in middle school, she experienced the onset of puberty, resulting in a significant growth spurt and the development of voluminous breasts. Her classmates bestowed upon her the nickname "Saipu," due to her hairstyle resembling that of a cyclops. In her younger years, her fondness for her older sibling and her desire to marry him were endearing; however, now that she fancies herself mature enough to fulfill her childhood pledge, it unnerves him.