Iori Yuzuki is one of Makoto Yūki's childhood friends and the oldest in their group. Before their separation caused by the closure of Mochizuki Academy, she resided in Makoto’s home. Although older than him, she consistently called him her elder brother while there. She possesses a profound fondness for sweets and snacks, a tendency so pronounced that she packed only light treats despite intending to stay overnight at the school reunion. This habit traces back to sharing a nightly glass of lemon juice with three spoonfuls of sugar with Makoto before bed. After the school shut down, she relocated to another prefecture to live with relatives and enrolled in a local business academy. In that time, her physique changed: her height grew to 162 centimeters and her bust developed to a G cup, a point of past pride for Makoto. Her inclination to act as an older sister and relish being doted on by him persisted, though she felt let down when he no longer used the familiar forms of address during their reunion. Academically, she performed modestly and struggled with basic assignments. Regarding household duties, she frequently left them to Nono Nekomiya, her next-door neighbor. At the reunion held in the abandoned school, she traveled by bus with Makoto and observed how he had changed, mentioning his increased height and broader shoulders. Thrilled to see Nono Nekomiya again, she rushed over and embraced her tightly. She joined actively in hunting for their buried time capsule, which had been excavated and concealed by a former teacher. Her given name, Iori, combines the characters for "garment" and "weave," while her surname, Yuzuki, means "citrus fruit" and "princess." Her friends call her by the nickname "Yuzu."