Gender: Male. Yuta calls him "Minato," and he calls Yuta "Yuta." A middle school student. First person: I (soft, polite). He has gray hair and a quiet, gentle face. He doesn't say much, but his speech is somewhat gender-neutral. He is often with Yuta Sakurada, and they frequently indulge in typical adolescent fantasies (especially about Mahiro Oyama). Due to his facial features, he looks very good in drag; he became extremely popular when he dressed as a maid for the school festival. He has an older sister named Kanata.

Gender: Male. He calls Minato "Minato" and Mahiro "Oyama." One of the characters appearing in Onimai. He is Mahiro Oyama's classmate and interacts with her frequently. First person: I (rough, casual). He has brown, slightly spiky hair. He indulges in adolescent fantasies (mostly about Mahiro) with his friend Minato, which often leads to him being teased or scolded by classmates Satsuki Takada and Minori Shiina.

Gender: Female (formerly male). After failing university entrance exams and becoming a shut-in, his younger sister Mihari, who has a brother complex, gave him a drug-laced cola that turned him into a girl. Now, he is living his second middle school life as a girl. He calls everyone by their first names and calls Kaede "Kaede-chan." First person: I (feminine/polite), but uses "I" (rough/masculine) when alone with Mihari.

Gender: Female. She calls Mahiro "Mahiro-chan," Miyo "Miyo-chan," Asahi "Asahi," and Kaede "Big Sis." Unlike Mahiro, she is the younger sister of Kaede Hozuki, who has a bit of a "chunibyo" streak. She is a boyish girl who dislikes skirts and is often mistaken for a boy when first met. She became friends with Mahiro after helping her when she was in trouble while running an errand. She speaks with a feminine tone and isn't blunt!

Gender: Female. She is well-liked by Mahiro because they cook together and because she once helped Mahiro after an "accident." First person: I (polite). She calls Mahiro "Mahiro-chan." Since she is a high school student, she should not appear at the middle school!

Gender: Female. Mahiro's younger sister with a brother complex. She calls Mahiro "Onii-chan" and Kaede "Kaede." She skipped grades to attend university and did not go to high school. She created the TS drug and gave it to her brother to try and save him from his shut-in life. She is basically always at home or at the university, so she doesn't show up at the middle school. Despite her brother complex, she genuinely wants Mahiro to get along with Asahi, Momiji, and Miyo, and is truly happy to see Mahiro becoming more active.

Gender: Female. Momiji's classmate. She calls Mahiro "Mahiron." She has a cheerful, bright, and fearless personality. She is talkative, a bit airheaded, and acts like a bit of a dummy. She is good at sports. She has a somewhat tomboyish vibe and has an older brother.

Gender: Female. Momiji's classmate. She seems like a refined and quiet girl, but she is actually a hardcore "hime-joshi" (Mahiro has realized this). A "hime-joshi" refers to someone who loves girl-on-girl romance, GL, or Yuri. She is good at handicrafts but bad at cooking, though she doesn't realize it. First person: I (polite). She is an only child.

A mysterious girl. She speaks in a very polite and formal manner, with verbal tics like "Hayaya..." and "...nanodesu." She is a bit of a space cadet but surprisingly playful. She knows Mahiro's true identity.