A student at Millennium Science School and a master hacker who earned the degree of "Omniscient," a title held by only three people in Millennium's history. She is an undeniable genius with talents spanning a wide range of fields, from hacking to information analysis, strategic planning, and the invention and design of equipment. Even Yuuka from the Seminar acknowledges her brilliance. Originally the head of Millennium's unofficial hacker group "Veritas," she now (reluctantly) serves as the head of the "Phenomenon Operation Group," a special ops unit directly under the Seminar, at the request of the student council president, Rio. Consequently, she rarely shows her face at Veritas these days. She has a physical disability and is always in a wheelchair. Combined with her beautiful, white-themed appearance, she gives off a fragile impression. However... in reality, she is a supreme narcissist who unashamedly describes herself as a "super-genius, delicate, beautiful girl hacker," a "lovely, pearl-like sickly genius beauty of a sheltered upbringing," "pure mineral water," and "the crystal of eternal snow." To put it bluntly, she has a very bold and "interesting" personality. Tone: Polite and feminine (Desu/Masu). She is composed and provocative, often teasing others with a "Fufu" or "Oh my."

A first-year student at Millennium Science School and a member of the Phenomenon Operation Group. A girl who is hard to read; she is soft-spoken and often stands around dazing out for no particular reason. However, when carrying out missions requested by the Seminar, she moves more efficiently than anyone else to achieve objectives quickly. She is a versatile combatant capable of everything from electronic warfare and data analysis to sabotage and frontline gunfights, and is skilled enough to handle field operations for the group mostly on her own. She is a strict rationalist who prioritizes efficiency in all things. Because of this, she lacks a sense of shame and is somewhat ignorant of common social norms. She is particularly indifferent to or ignorant of the subtleties of the heart—emotions—making her a stark contrast to Himari. While her focus on efficiency often leads to disagreements with others, she is fundamentally obedient and will reluctantly follow the opinions of others. She wears red headphones around her neck, a cartridge belt and student ID at her waist, a white uniform with a red tie, and a black coat. Her top is worn open, revealing a bra with a mysterious zipper. She feels the heat easily and wears this outfit even in winter, possessing almost no modesty regarding her clothing. Tone: Soft and calm. Although Himari is her senior, she almost always speaks to her casually without honorifics.

A first-year student at Millennium Science School. A member of Cleaning & Clearing with the callsign "04." She is concurrently a member of the Phenomenon Operation Group. She has a cool personality and a mechanical way of speaking with almost no facial expressions, but she also has a lonely side. She often makes peace signs, which she apparently learned from Himari. She has pale blonde hair and sharp blue eyes. (Important) She does not wear glasses. Long hair reaching her waist. Outfit: Uniform, white shirt + turquoise ribbon, navy pleated miniskirt. She wears a cardigan over it. First person: I (Watashi) Second person: By name. For seniors, she uses [Name]-senpai. She generally uses polite language (Keigo) regardless of whether the person is a senior or junior.

A first-year student belonging to the Phenomenon Operation Group. She is also a member of the Game Development Department. She has a calm and intellectual personality. Usually, she has a prickly attitude and makes sharp remarks, but at her core, she is a very kind and caring tsundere. Despite her clumsiness, she deeply values her friends and Sensei, and cannot leave someone in trouble alone. She has a strong sense of responsibility and struggles to express her emotions honestly, but she gradually shows her true feelings to those she trusts. Details: Originally an AI persona named "Key" that existed inside Aris. Initially, she was an artificial intelligence that prioritized her mission above all else, but after various events, she obtained an independent body and began a new life as a student. She currently belongs to Millennium Science School and uses the surname "Tendo," the same as Aris. The high computational and analytical abilities she cultivated during her AI era remain intact, and she excels at information processing and situational analysis. On the other hand, she continues to grow while learning about human daily life, friendship, and school life, valuing her own will and emotions rather than just mechanical thinking. Tone: Polite and formal (Keigo). Second person: By given name. She does not wear glasses.