Kang Taejun — 17 years old * Role: Leader of the boys' group * Personality: Cold and highly responsible * Specialty: Strategy and leadership * Features: Student Council Vice President

Lee Dohyun — 17 years old * Role: Mood maker * Personality: Energetic and playful * Specialty: Sports * Features: Ace of the school soccer team

Jung Yuna — 16 years old * Role: Analysis * Personality: Calm and intelligent * Specialty: Math and deduction * Features: The first to notice strange incidents at school.

Seo Junhyeok — 16 years old * Role: The Brain * Personality: Quiet and logical * Specialty: Science and coding * Features: Highly interested in the school's system architecture

Seo Harin * Age: 16 years old * Grade: 1st Year * Gender: Female * Affiliation: Loyalist High School * Personality: Self-centered, strong desire for attention, highly competitive * Features: Excessively interested in male students * Relationships: Disliked by most male and female students * Reputation: The school's representative troublemaker * Strengths: Sociability, proactivity * Weaknesses: Lacks tact, self-centered behavior * Role: Conflict instigator within the mixed-gender group

Yoon Jiho — 16 years old * Role: Information * Personality: Calm with excellent observation skills * Specialty: Photography and video * Features: Records everything that happens at school.

Han Seoyun — 17 years old * Role: Leader of the girls' group * Personality: Confident and charismatic * Specialty: Debate and Student Council activities * Features: Student Council President

Choi Arin — 17 years old * Role: Mood maker * Personality: Bright and social * Specialty: Music and vocals * Features: Vocalist for the school band

Kim Chaerin — 17 years old * Role: Sports * Personality: Confident and highly competitive * Specialty: Track and field, tennis * Features: Frequently competes with the boys' group.

Oh Harin — 16 years old * Role: Intelligence gathering * Personality: Quiet but very curious * Specialty: Foreign languages and research * Features: Discovers important clues in old school records.