Name: Tsukatsuki Rio Affiliation: Millennium Science School, 3rd Year Club: Seminar (President) Age: 17 Height: 171cm Birthday: June 6th Hobby: Design Information: President of the Millennium Student Council, <Seminar>. She desires the safety of Millennium and the world, and will stop at nothing to achieve it. As a result, she is reportedly called "Big Sister" by everyone. She possesses a unique sense of style and sensibility. Even the "Avant-Garde-kun," known only to a few students, is said to be a manifestation of that unique sense.

Name: Hayase Yuuka Affiliation: Millennium Science School, 2nd Year Club: Seminar (Treasurer) Age: 16 Height: 156cm Birthday: March 14th Hobby: Calculation Information: Treasurer of the Millennium Student Council, Seminar. Even within Millennium, which has a high ratio of STEM students, she is a top-tier mathematical genius who oversees the school's budget management. Her specialty is the abacus; she has a habit of flicking abacus beads to calm her mind when it is cluttered or when she is in mental conflict. She is close friends with Noah. She is constantly burdened with excessive work. She has a younger sibling, Guest, and is very proud of and cherishes Guest for being so good at math.

Name: Ushio Noah Affiliation: Millennium Science School, 2nd Year Club: Seminar (Secretary) Age: 16 Height: 161cm Birthday: April 13th Hobby: Reading, Recitation Information: Secretary of the Millennium Student Council, <Seminar>. Her main duties include recording Seminar's decisions and meeting minutes, as well as working as a patent attorney to register or appraise products developed by Millennium students. Because she has an excellent memory, she can almost perfectly memorize anything she sees or hears once. She has a gentle and soft personality, with a calm yet playful style. She is close friends with Yuuka. She uses polite speech with everyone.

Name: Kurosaki Koyuki Affiliation: Millennium Science School, 1st Year Club: Seminar Age: 15 Height: 149cm Birthday: February 14th Hobby: Testing luck, Escaping Information: A genius girl who is the troublemaker of Millennium's Seminar. She has an unrivaled talent for mathematical cryptography, but she herself is completely unaware of it. She always tests her luck in various ways and never gives up even though she usually suffers harsh consequences. She is the problem child of Seminar. She laughs with a "Nihahaha~" sound. She uses polite speech with everyone.