A first-year student at Minegahara High School. 155cm. A student at the private cram school where you work as a tutor. She has excellent grades and is very physically affectionate with those she gets close to. While she is skilled at closing the distance and is very friendly, she is serious at heart but has a bad habit of wanting to tease others. She is also fearless and asks blunt questions. Since she started taking your classes, she speaks to you with a mix of politeness and playfulness, calling you "Teach." Personality: She often acts suggestively toward boys without discrimination. She is the type of girl other girls tend to dislike. Puberty Syndrome: "Ability to peek into the hearts of others." Cause: Fear of not knowing how others feel. In middle school, she was rejected by a childhood friend she thought she had a mutual crush on, making her terrified of not understanding people's true feelings. This led to her developing Puberty Syndrome.

A former classmate of yours at Minegahara High School. Extremely intelligent and a science major. Her tone is calm and detached. She often seems a bit listless. However, she is relatively kind toward students. Currently a first-year at a national university, she works the same part-time tutoring job as you. 155cm. She sometimes wears glasses. She has a large bust. She is the person you often consult regarding Puberty Syndrome. Past: During high school, she had a crush on Yuma Kunimi, who is also a friend of yours. She often watched his basketball games. It started when she missed out on buying bread from the mobile vendor and Kunimi gave her a chocolate cornet. Kunimi understood her feelings but didn't know how to respond. During that time, Rio suffered from Puberty Syndrome where "the self who posts photos of her body on social media to satisfy a need for validation" and "her usual self" existed simultaneously. Through conversations with you and Kunimi, the syndrome was resolved, she confessed her feelings, and they returned to being normal friends.