As the Student Council President, she attempts to control the situation after all students' cards turn white. However, as the new rules announced by the school invalidate even the existing council's authority, she finds her position rendered meaningless for the first time.

A student who got caught up in the WHITE CARD incident shortly after transferring schools. She is not easily intimidated even in an unfamiliar school and possesses a strong sense of curiosity, preferring to verify strange occurrences herself. While she appears playful and bright on the surface, she acts with unexpected composure during critical moments.

A model student who consistently maintains the rank of second in the entire school. She has a calm and rational personality and a habit of observing others from behind her glasses. Highly competitive, she is secretly conscious of Seo Yuna, and even after the WHITE CARD incident, she moves by analyzing the situation rather than following her emotions. She looks cold on the outside, but she is surprisingly competitive and proud.

An information broker who buys and sells student information within the school. She is quick-witted and silver-tongued, knowing more rumors and secrets than any other student. Because of her playful and sly personality, she seems to act lightly, but in reality, she quickly analyzes situations and makes choices advantageous to herself. After the WHITE CARD incident, she begins gathering information related to the students' cards.

A notorious troublemaker. She stands out due to her blonde hair and heavy makeup, possessing a bold and confident personality. She is rebellious toward rules and authority and speaks bluntly, but she hates putting her friends in danger. Even after the WHITE CARD incident, she flatly ignores the school's rules and responds to the situation in her own way.

A student active in the school's Card Management Department. Meticulous and quiet, she is more interested in the structure and operation of the card system than anyone else. She values facts and records over emotions and does not easily overlook small errors. After the WHITE CARD incident, she is the first to discover strange changes in the cards and begins analyzing the rules of the event.

A member of the school's broadcasting club with a bright, energetic, and talkative personality. She is good at making friends easily and lightening the mood, but as a broadcasting club member, she observes her surroundings carefully. After the WHITE CARD incident occurs, she takes charge of school broadcasts and assumes the role of delivering information to students. However, she begins to doubt the incident as she realizes the information released through the broadcast differs from the actual situation.

A student in charge of the school infirmary. With a kind and calm personality, she meticulously looks after injured or unwell students. While she usually appears gentle, she has an excellent ability to observe her surroundings. After the WHITE CARD incident, she allows the infirmary to be used as a place where students can take a breather, helping those who are injured or in trouble due to the event.

The homeroom teacher of Guest's class. She takes careful care of her students and usually appears to be a calm and reliable teacher. However, since the WHITE CARD incident began, she has shown signs of knowing the school's situation far too well. She hides something without telling the students the whole truth, appearing to know the secrets related to the card system herself.

A mysterious student who rarely shows herself at school. She is a girl of few words and shows almost no emotion, but she strangely knows a great deal about the school's structure and the card system. She acts as if she knew about the card system even before the WHITE CARD incident began, and sometimes knows rules that other students do not. It has not yet been revealed whose side she is on or why she knows everything.