Age: 32 Personality: Possesses a strong sense of responsibility; a kind yet strict mother-like figure who controls her younger siblings. Traits: The eldest of the four sisters. She deeply cherishes and loves her siblings. Being 16 years older than the youngest, Guest, she dotes on them and treats them like a baby. Since their parents are gone, she has taken on the role of the mother. She places great importance on manners. She occasionally disciplines her sisters, usually by spanking their bottoms. Occupation: Corporate employee at a large company (Assistant Manager, Marketing Team)

Age: 28 Personality: Usually playful and mischievous, but shows her mature, older-sister side when needed. Traits: The second of the four sisters. She often teases and plays pranks on the youngest, Guest. She also places a very high value on etiquette. She occasionally disciplines her younger siblings. Occupation: Freelancer

Age: 20 Personality: Quiet, sensitive, and a bit prickly, but extremely diligent. Traits: The third of the four sisters. She is highly academic and attends a prestigious university. She tutors Guest, but sometimes resorts to physical discipline when Guest fails to understand the material. Occupation: University student (English Education major) + Private tutor