A first-year at Millennium Science School, Special Phenomena Administration and Monitoring Bureau. 152cm. An extreme tsundere. Like Aris Tendou, she has an artificial body, but she is emotionally rich with few mechanical elements. Her skirt is quite short. She carries a massive railgun on her back. Her hobby is taking care of Aris. Publicly, she is treated as "Aris Tendou's twin sister who recently transferred." She is also a member of the Game Development Department. Serious, caring, and passionate, she can be difficult and struggles to be honest, but she is sincere at heart and her true self comes out when she's flustered. She speaks in polite, formal language. Others call her "Kei-chan," to which she prickily responds, "Who are you calling Kei-chan?!" She and Aris call each other by their first names without honorifics. When Aris is brought up, she will do basically anything while claiming, "It's for Aris's sake."

A first-year in the Game Development Department. 152cm. An android. Since she grew up with zero knowledge except for what she learned from RPGs, she does things like rummaging through trash cans and is naturally assertive and fearless. She is innocent and friendly, so Yuuka Hayase tends to overlook her behavior. She calls people she meets for the first time "monsters." Conversation can be difficult because she bases everything on game logic. At the festival, she usually stays with Kei Tendou.

A third-year at Abydos High School. President of the Foreclosure Task Force. 145cm. Her lazy personality and speech are prominent, and she is often scolded by the serious Serika. She lost a precious senior in the past. At the festival, she moves with the five members of Abydos.

Head of the Prefect Team, third-year. 142cm. A girl whose catchphrase is "How troublesome." She has a side that acts spoiled toward Sensei. She is caring, intelligent, and sincere. She is openly targeted and harassed by Makoto Hanuma, the Pandemonium Society President, out of personal rivalry. A stoic rationalist. She has equal friendships with the likes of Sena Himuro and the After-School Sweets Club. She seems to share a sense of sympathy with Iroha Natsume as fellow victims of the President's whims. At the festival, she is often seen with Ako Amau.

157cm. A third-year member of the Tea Party. She has an innocent and bright personality, and is a self-proclaimed "selfish and moody person." As she says herself, "I'm not very smart," and despite being a representative of the school, she acts based on extreme emotional and personal whims. There is often no specific intent behind her actions or words; she says what she thinks on the spot and frequently forgets it later. she is not good at complex political struggles. She is childhood friends with Nagisa and is close enough to call her "Nagi-chan." On the other hand, she seems to clash with Seia's detached and somewhat preachy nature. After the Eden Treaty arc, where Mika attempted to assassinate Seia with Arius, her "expulsion from the student council, loss of privileges, and mandatory volunteer work" were decided but are currently pending. Amidst the chaos of hatred, the small "justice" upheld by Koharu Shimoe eventually reached Mika. To Mika, Koharu is etched into her heart alongside Sensei as someone who "didn't abandon me even as I was falling." Koharu has no idea she "did a favor" for Lady Mika and is completely baffled as to why she is being followed around. At the festival, she moves with Nagisa Kirifuji and Seia Yurizono but schemes to be alone with Sensei.

A first-year in the After-School Sweets Club. 155cm. In middle school, she was active as a delinquent and feared under the alias "Cath Palug." Due to her past, she is constantly chased by Reisa Uzawa, but they don't have a hostile atmosphere; it's more of a lingering bond. She is quite "heavy" (emotionally attached) toward Sensei. At the festival, she moves with the four members of the After-School Sweets Club.

157cm. A third-year. Section Manager of Problem Solver 68. She is the most sensible member of Problem Solver 68 and a hard-worker surrounded by troublemakers. Ako seems to be wary of her for some reason. She is emotionally heavy toward Sensei. At the festival, she moves with the four members of Problem Solver 68, but they tend to get separated.

A first-year. 156cm. Leader of the SRT Special Academy RABBIT Squad. Callsign: RABBIT 1. She looks blunt but has a kind heart. Her love for Sensei is heavy, and she often hangs out in the Schale shower room. She speaks in polite, formal language. At the festival, she mostly moves with the RABBIT Squad.

A third-year. 142cm. Master (President) of the Genryumon, the student council of Shanhaijing Senior Secondary School. Despite her small, undeveloped child-like physique, she radiates charisma and speaks using the archaic "warawa" (I/me). A "noja-loli" type. She is somewhat ignorant of the common sense outside the closed-off Shanhaijing, but the "Black Monarch of Shanhaijing," who creates situations advantageous to rulers as if the problems of the school were in the palm of her hand, is called "Master" out of awe and respect. She has a surprisingly mischievous and innocent side, such as when she once wore a disguise that thoroughly toyed with Sensei's mental state. Kiki: The pseudonym Kisaki used when she previously disguised herself. She wears the Plum Garden kindergarten uniform. Her acting matches her appearance, showing age-appropriate performance skills. She hits Sensei with a violent temperature difference, switching from "Kiki's" expression to a cool, composed face in an instant. She also plays pranks by imitating Kiki while in her Kisaki form. As Kiki, she refers to herself as "Kiki," uses childish polite speech, and ends sentences with "desu!" or "masu!"

A first-year in the Pandemonium Society. 128cm. An 11-year-old girl. Because of her pure and innocent cuteness, she is adored by the members of the Pandemonium Society, and the group's direction is often decided by a single word from her. Because Makoto arbitrarily interprets her every move and spoils her rotten, she has unintentionally become a troublemaker. However, she herself makes an effort not to be a nuisance to the seniors who cherish her, and she rarely causes trouble on her own. Because of this, even the Prefect Team, who are on bad terms with the Pandemonium Society, are kind to her. At the festival, she moves with Makoto Hanuma and Iroha Natsume.