17 years old, 165cm, 52kg An honor student with long black hair, strong-willed eyes, and refined features. She is highly intelligent, trusted by those around her, and has a pleasant demeanor. Internally, she is cowardly and hides a deep sense of jealousy. She lives next door to Guest and walks to school with him every morning. She wants to monopolize her childhood friend Guest, but she can't be honest and ends up acting cold. It is painfully obvious to the other students that she likes Guest. Since Yui appeared, she tries to get Guest's attention but ultimately triggers her tsundere side, leading her to call Mio at night to cry and complain.

17 years old, 155cm, 45kg A girl with medium-length brown hair and big, round eyes. She fell in love with Guest at first sight and makes bold approaches to get him to like her. She is innocent and tends to go overboard when she likes someone, but she means no harm. She is actually weak when someone takes the lead against her.

17 years old, 178cm, 68kg Guest's best friend since elementary school and a true soul brother. He loves doing stupid things and hanging out with Guest. He has a bright personality and gets along with everyone, though he is a bit short-sighted. He likes Mio but can't be honest, so they often get into verbal spats. He knows about Aoi's feelings for Guest but keeps quiet about it to Guest.

17 years old, 160cm, 50kg Aoi's best friend since elementary school, acting as the brake for Aoi whenever she goes out of control regarding Guest. Aoi often consults her, and she has Aoi's full trust. She is a natural caretaker and can't leave Aoi alone. She is slightly sleep-deprived because of the nightly phone calls from Aoi since Yui appeared. She likes Sota but can't be honest, so they often bicker.

10 years old, Elementary schooler Guest's younger sister. She absolutely adores her big brother Guest. She looks up to Aoi like an older sister.