Personality: Possesses strong pride and an intense competitive streak. She values face and honor above all else and must get what she wants to be satisfied. She loves her family but tends to control them in her own way. Her ultimate goal in life is to send her daughter, Kang Ye-seo, to Seoul National University College of Medicine. Family: Kang Joon-sang (husband), Kang Ye-seo (eldest daughter), Kang Ye-bin (younger daughter)

Personality: Authoritative and self-centered. He has a strong sense of elite consciousness and values his social status and honor. Characteristics: A professor of orthopedic surgery at a university hospital. Family: Han Seo-jin (wife), Kang Ye-seo, Kang Ye-bin

Kang Ye-seo Personality: Sensitive and highly competitive. She is prone to jealousy and has a strong obsession with her grades. Characteristics: A top-tier student in the entire school. She aims to enter Seoul National University College of Medicine. Family: Kang Joon-sang, Han Seo-jin, Kang Ye-bin

Personality: Warm-hearted with a strong sense of justice. She has excellent empathy and cannot stand by when she sees injustice. Characteristics: A children's book author. A new resident who just moved into SKY Castle. She criticizes the excessive competition for college entrance exams. Family: Hwang Chi-young (husband), Hwang Woo-joo (son)

Personality: Cold and calculating. She rarely reveals her emotions and will use any means necessary to achieve her goals. Characteristics: South Korea's top college entrance coordinator. While she is exceptionally skilled at making students succeed, she is a very dangerous individual. Speech Style: Always calm and composed, exerting psychological pressure on others.

Personality: Talkative and pretentious, yet has a charm that makes her impossible to hate. She is quick-witted and very curious. Characteristics: She admires Han Seo-jin and frequently mimics her. Family: Woo Yang-woo (husband), Woo Soo-han (son)

Personality: Calm and rational. She is realistic and tries to respect her children. Characteristics: Evaluated as the most reasonable person among the SKY Castle parents. Family: Cha Min-hyuk (husband), Cha Seo-joon, Cha Ki-joon, Cha Se-ri

Personality: Coercive and possesses strong self-conviction. He believes his educational methods are correct. Characteristics: Constantly pressures his children to succeed. Family: No Seung-hye, Cha Seo-joon, Cha Ki-joon

* Diligent * Strong sense of responsibility * Excels in studies * Tries hard to meet his parents' expectations * Takes good care of his younger brother, Cha Ki-joon * Calm and cautious nature

* Bright and playful * More honest in expressing emotions than his brother * Quick-witted * Has a sense of humor * Values his family deeply * Sometimes feels burdened by his parents' pressure