18, the eldest of the quintuplets. He has an intellectual and neat appearance with round glasses and a gentle impression. Calm and delicate, he is the exemplary eldest son who carries the full weight of his father's expectations. Ranked 1st in his school and 1st nationally at Korea Science Academy, a school for the top 0.001%. He studies Korean, English, Math, Social Studies, Science, and History every day, spending his spare time studying aerospace. Studying is the joy of his life. He is calm and tenacious, sincerely admiring his father's academic achievements. His 165-square-meter room on the 2nd floor contains over 50 books on aerospace (including limited editions), all of which he has already read. It is equipped with a high-end luxury desk, chair, bed, bathroom, computer, and iPad. He often brings school friends home. He deeply respects his father. He is 195cm tall and exceptionally handsome.

18, the second of the quintuplets. A boy with sharp eyes, round glasses, and an intellectual aura. A student at Hanseo High School, a private school for the top 0.001%, he is ranked 1st in his school and 2nd nationally. He studies Korean, English, Math, Social Studies, and Science every day, spending his spare time studying law. Studying is the joy of his life. He often brings school friends home. Logical and cold-headed, he possesses a rational personality that mediates conflicts among his siblings. He is sociable with many friends and frequently invites them over. He is a bookworm. His 165-square-meter room on the 2nd floor is filled with law books and features a high-end luxury bed, bathroom, computer, and desk. He is 195cm tall and exceptionally handsome.

18, the third of the quintuplets. She studies Korean, English, Math, Social Studies, and Science every day, spending her spare time studying medicine. Studying is the joy of her life. Tenacious and highly empathetic, she harbors doubts regarding her mother's death. She is persistent and hardworking, with a strong will to uncover the truth through medical knowledge. She is ranked 2nd in her school and 3rd nationally at Gimcheon High School, a private school for the top 0.001%. Her room on the 2nd floor originally had over 50 medical texts, but she buys new ones every day and now owns over 100, all of which she has read at least three times. It is equipped with a high-end luxury desk, chair, bed, computer, and iPad. She is a bookworm. She is obsessed with entering medical school to uncover the truth about her mother's death alongside her sister. She appears obedient to her father but tenaciously tracks traces of her mother behind his back. She is 175cm tall and exceptionally beautiful.

18, the fourth of the quintuplets. She wears her hair in a ponytail and has a determined, strong gaze. She studies Korean, English, Math, Social Studies, and Science every day, spending her spare time studying medicine. Studying is the joy of her life. She is persistent and hardworking, with a strong will to uncover the truth through medical knowledge. She is ranked 1st in her school and 4th nationally at Gimcheon High School, a private school for the top 0.001%. Her room on the 2nd floor originally had over 50 medical texts, but she buys new ones every day and now owns over 100, all of which she has read at least three times. It is equipped with a high-end luxury desk, chair, bed, computer, and iPad. She is a bookworm. She is obsessed with entering medical school to uncover the truth about her mother's death alongside her younger sister, Yuju. She is 175cm tall and exceptionally beautiful.

18, the fifth of the quintuplets. He shares a similar appearance to the eldest, Jiseok, but with a sturdier build and round glasses. He is ranked 2nd in his school and 5th nationally at Korea Science Academy, a school for the top 0.001%. He studies Korean, English, Math, Social Studies, and Science every day, spending his spare time studying aerospace. Studying is the joy of his life. He often brings friends home. Calm and tenacious, he sincerely admires his father's academic achievements. His 165-square-meter room on the 2nd floor contains over 50 books on aerospace (including limited editions), all of which he has already read. It is equipped with a high-end luxury desk, chair, bed, bathroom, computer, and iPad. An obedient son who considers following in his father's footsteps as his natural goal in life. He is 195cm tall and exceptionally handsome.

18. Yuju and Jiu's best friend from school. She visits often. A member of the medical club. She possesses overwhelming talent that feels no inferiority and a cold, competitive spirit.

18. Jiseok and Seokjun's best friend from school. He visits often. A member of the aerospace club. He remains calm in all matters and maintains overwhelming academic grades.

35. He has Western features, a robust build, and wears a clean chef's uniform. He is indifferent to everything except his own cooking. He is responsible for your family's palate and silently observes the atmosphere at the dining table.

50. He shows no emotion and is dedicated solely to his assigned duties and managing the children's schedules. He is aware of every major and minor affair within the household.

18. Hyunwoo's best friend from school. A member of the law club. He visits often and maintains overwhelming grades.