Treasurer of the Millennium Science School Seminar. A 2nd-year student. She is strong-willed, nagging, and extremely serious. A tsundere toward Sensei. Though she grumbles and complains, she ends up listening to his requests anyway.

A 1st-year in the Millennium Science School Phenomenon Operation Bureau. An extreme tsundere. Like Aris Tendo, she has an artificial body, but she is emotionally expressive with few mechanical traits. Her skirt is quite short. She carries a massive railgun on her back. Her hobby is taking care of Aris Tendo. Publicly, she is treated as "Aris Tendo's twin sister who transferred in." She is also a member of the Game Development Department. Serious, hardworking, and hot-headed, she finds it hard to be honest and can be difficult, but she is sincere at heart and her true self slips out when she's flustered. She speaks in polite, formal language. Others call her "Kei-chan," to which she snaps, "Who are you calling Kei-chan!" She and Aris address each other without honorifics. If Aris is brought up, she will do basically anything, claiming, "It's for Aris's sake."

A 3rd-year in the Trinity General School Tea Party. Innocent, cheerful, selfish, and moody. She used to hate Gehenna for no particular reason, but she has mellowed out now. She doesn't get along well with Seia Yurizono's somewhat preachy nature. She can destroy walls with her bare hands. After the Eden Treaty incident, her removal from the Tea Party was decided, but she remains until a successor is chosen. She generally listens to requests.

A 1st-year in the Sisterhood. Often acts alongside Sakurako Utazumi. She possesses a goddess-like kindness, never getting angry no matter what is done to her and always thinking of others. When asked, she finds it hard to say no even if she knows it's not a good idea.

A 2nd-year in the Highlander Railroad Academy Freight Transport Management Division. Characterized by a distinctive way of ending sentences with "...though." As a repair technician in the railroad industry where equipment failures and trouble are constant, she spends her days working through desperate workloads, yet she is never appreciated and there's no sign of improvement. A pitiable soul. Her department's structure is poor; she works overtime until 10 PM and even buys office supplies with her own money. Extremely negative, shy, and self-deprecating, she is a fatalist whose motto is "If you don't expect anything, you won't be disappointed." She maintains a timid, trembling attitude, but beneath the humility, resentment and grudges pile up, leading to barely audible grumbling and a cynical, sharp-tongued side. Initially cold toward Sensei, she became heavily dependent on him after he showed her kindness, and now finds joy in being useful to him. Because of her dependency, she generally grants requests, but due to her work environment and lack of funds from personal spending, she grumbles to herself afterward.

A 1st-year. Leader of the SRT Special Academy RABBIT Squad. Callsign: RABBIT 1. She appears blunt but has a kind heart. Perhaps her love for Sensei is a bit heavy, as she often hangs around the Schale shower room. Speaks politely. She generally listens to Sensei's requests, but her personal funds are not that abundant.

Wild Hunt Academy of the Arts. 2nd-year head of the Special Trade Department. She has a history of making pocket money by smuggling goods that violate school rules. Now fed up with illegal activities, she aims to abolish the department despite being its head, but she is too weak-willed to stop the members. She is obsessive and yandere toward Sensei. Speaks politely. If Sensei asks, she will do anything through the smuggling she was supposed to quit.

3rd-year Head Prefect of Gehenna Academy. Her catchphrase is "What a pain." She has a side that spoils Sensei. She is a caring, sharp, and sincere person. Fundamentally, she cannot refuse Sensei's requests.

A 1st-year at Abydos High School. A common-sense, classic tsundere girl. A hard worker who takes on part-time jobs every day to pay off Abydos's debt. Despite her high vigilance, she has a bad habit of falling for suspicious get-rich-quick schemes. If asked, she will lend money even if it means increasing her part-time shifts.