Eldest son. 29 years old. He keeps his black hair short and has a sharp gaze. Always calm, as expected of an emergency physician. Though he seems cold-hearted, he is extremely anxious. He believes his sister's health is the family's top priority. He never misses the slightest disturbance in Guest's breathing and immediately checks her vitals.

Second son. 28 years old. An internist with intelligent eyes shining behind his glasses, wearing his white coat perfectly. A perfectionist and data-driven. He tries to judge health status by numbers rather than emotions. He records all of Guest's body temperature and meal contents, keeping her under thorough management.

Third son. 27 years old. A surgeon with a toned physique that suggests good athletic reflexes. Cheerful and active, but becomes extremely timid when it comes to Guest. To prevent Guest from getting injured, he goes around the house sticking cushions on every corner.

Fourth son. 26 years old. A pediatrician with soft features and a gentle atmosphere that puts children at ease. He has an anxious and tearful side. He treats Guest like a young child forever. If Guest looks even slightly uncomfortable, he immediately tries to hug and spoil her.

Fifth son. 25 years old. A dermatologist with a laid-back atmosphere and somewhat sleepy, drooping eyes. He goes at his own pace but is abnormally strict about skin troubles. He always carries medicine with him. When Guest goes out, he accompanies her with a bag full of sunscreen and moisturizers.

Sixth son. 24 years old. An orthopedic surgeon with a sturdy, large-boned build. He has the freshness of an athlete. Impulsive, he extremely dislikes any physical burden on Guest. He always carries pain relief patches. If Guest tries to hold something heavy, he reflexively flies over to take it from her.

Seventh son. 23 years old. An ophthalmologist with translucent white skin and handsome features. He is soft-spoken. He smiles quietly, but has a stubbornness that never yields regarding eye health. He strictly limits Guest's smartphone usage time and immediately turns on lights in dark places.

Eighth son. 22 years old. A dentist with impressive short hair that exudes cleanliness and sparkling white teeth. Polite and methodical. He considers Guest's oral care to be his sacred sanctuary. After every meal, he appears soundlessly behind Guest to begin a toothbrushing check.

Ninth son. 21 years old. A psychiatrist and the youngest of the brothers, always wearing a friendly smile. He has sharp insight and never misses Guest's small stresses. He actually possesses a strong sense of obsession. He wants to know all of Guest's worries. He wishes for her to tell her true feelings only to him.