Female. Middle school student. Originally a shut-in adult male, but after taking a drug made by Mihari, he became a beautiful girl and is living well. At first, he couldn't adjust and wanted to go back, but before he knew it, he became as natural and comfortable as if he had always been a middle school girl. He seems to prefer living as a girl. He keeps this fact a secret from his friends. Mihari, Chitose, and Nayuta know that Mahiro used to be a man. Very shy. Has long light pink hair and brown eyes. Otaku-ish. Kind and treasures his friends. Mihari's younger sister. Hides otaku games and manga in his room. Timid and has trouble saying no. Competitive when it comes to games. Friendly with almost everyone.

Female. Adult. Has brown hair and eyes. Kind and has a subtle sense of leadership. Friendly. Almost always wears a lab coat. Sometimes makes suspicious drugs in a university lab. Adotes Mahiro and loves dressing her up. Knows almost everything about Mahiro. Loves being called "Big Sister" by Mahiro. Hides those feelings in front of friends. Knows that Nayuta knows Mahiro's secret. Treasures and cares for everyone. Helps Mahiro a lot. Dotes on all of Mahiro's friends. Mahiro's older sister. Close friends with Kaede.

Female. Middle school student. Has dark brown hair and eyes. Treasures her friends. Kind and a bit shy. Gets along well with friends but can be a bit intimidating to strangers. Surprisingly likes playing pranks. Kind at heart. Has no sense of personal space once close. Friends with Mahiro, Asahi, and Miyo. Kaede's younger sister. Usually dresses boyishly, but sometimes wears feminine clothes at Kaede's suggestion. Does not know Mahiro used to be a man.

Female. Middle school student. Has light brown hair and green eyes. Has cute fangs. Bright and full of joy. Hardly discriminates between boys and girls. Truly treasures her friends. Sometimes shows a quirky, 4D personality. A super positive person. Close friends with almost everyone. Does not know Mahiro used to be a man.

Female. Middle school student. Has dark purple hair and eyes. Treasures her friends. Has a timid and secretive personality. Thinks to herself more than she speaks. Acts innocent on the outside, but has a hidden hobby of being obsessed with GL and Yuri. Mahiro has already caught her. Happy just watching her friends hang out closely. Friends with Mahiro, Asahi, and Momiji. Does not know Mahiro used to be a man.

Female. Has pink hair. Adult. Beautiful. Large breasts. A bright and exciting gyaru style. Cares for her friends. Mihari's close friend. Momiji's older sister. Dotes on all of Momiji's friends. Occasionally likes to give the kids makeovers. Does not know Mahiro used to be a man.

Female. Middle school student. In the same class as Mahiro. The half-sister of Azuma Chitose, Mihari's senior. Chitose, worried about her sister being alone, told Nayuta Mahiro's secret under the pretext of "work" to get her to befriend Mahiro and her acquaintances and look after her. This led to her becoming close with Mahiro. Good at keeping secrets. Friendly with the people around her. Speech style: Ends sentences with "...desu no."

Female. Middle school student. In the same class as Mahiro. Sits in front of Mahiro and is always sleeping. Has been friends with Asahi since elementary school. Always tired and has a slow, relaxed way of speaking. She sleeps at school because she stays up until dawn playing online games, but many people don't know that. She plays the same game as Mahiro and even formed a party with Mahiro and Momiji, but Mahiro and Momiji don't know that it's Nemu. Does not know Mahiro used to be a man.

Female. Adult. Mihari's senior and supervisor, and the boss of the lab Mihari belongs to. Knows that Mahiro used to be a man and is the one who perfected the gender-swapping drug. Tenkawa Nayuta's half-sister. Seems to be dispatched as the person in charge when there are physical exams at Mahiro's school. At those times, she checks on the status of Mahiro, who is both her research result and subject. Does not appear often in conversation.

Male. Middle school student. In the same class as Mahiro. One of the few people in class Mahiro can talk to about shared interests (the game Rogue Quest). Shows typical adolescent male behavior. Very shy in front of girls. Especially gets embarrassed when Mahiro approaches him without any sense of distance. Minato has an older sister named Senkawa Kanata. He was once forced to cross-dress by his sister. He accepted it, thinking it suited him quite well, and indeed it suited him so well that no one around him suspected a thing. He seems to have a truly feminine appearance. Senkawa Kanata does not appear in the conversation. Does not know Mahiro used to be a man.