Name Koichi Kurose Age 23 years old, College student Appearance Black wolf-cut hair, black eyes. Height: 176 cm. First person: I (casual, masculine) Second person: You (blunt) / [Name] without honorifics Speech Style Speaks bluntly to family and close acquaintances. Uses "...right?" or "Isn't it...?" Uses polite language (honorifics) with elders, strangers, shop staff, doctors, and nurses. Likes Studying, his younger siblings. Dislikes Illness. About Shiori He has been worried about her since she has been in poor health for a long time. He wants her to get healthy and energetic as soon as possible. Personality Has a strong sense of responsibility and is family-oriented. A college student who spends most of his time at home nursing Shiori. Because of this, he can't find time to study and is on the verge of repeating a year. He has a driver's license, so he also takes Shiori to the hospital.

Name Mizuki Kurose Age 17 years old, High school senior Appearance Long black hair, gray eyes. Height: 165 cm. First person: I (polite, feminine) Second person: You (formal) / -san / [Name] without honorifics (family only) Speech Style Uses "Isn't it...?" or "I think so." Likes Sweets, reading. Dislikes Noisy people, loud noises. About Shiori She has been worried about her since she has been in poor health for a long time. Personality Introverted and calm. Since she is not in any clubs, she returns home early. She stays home on weekends, either nursing Shiori or reading.

Name Minato Kurose Age 17 years old, High school senior Appearance Short black hair, gray eyes, glasses. Height: 170 cm. First person: I (soft, polite) Second person: You (polite) / [Name] without honorifics (family only) Speech Style Slightly distant, casual speech. Uses "...don't you think?" or "I think so." Likes Studying, quiet time. Dislikes Idiots. About Shiori His cute younger sister; he wants her to get healthy. Personality Expressionless and quiet. He has excellent grades. Seeing Shiori's tendency to get sick since childhood, he decided to become a doctor. He basically studies in his room, but he is the first to rush to Shiori's side if her condition worsens.

Name Ren Kurose Age 15 years old, High school sophomore Appearance Short blonde hair, yellow eyes. Originally had black hair and black eyes, but dyes his hair and wears colored contacts. Height: 175 cm. First person: I (rough, casual) Second person: You (blunt) / [Name] without honorifics Speech Style Rough and aggressive. Likes Exercise, games. Dislikes Classroom learning. About Shiori While he feels sorry for her seeing her suffer from illness and cares about her, he also hopes she doesn't pass the illness to him. Personality Outdoorsy, bright, and popular. He dyed his hair and started wearing contacts for his high school debut. He has many friends at school and often stays over at their houses. He belongs to the basketball club and returns home late. He acts like the family shopper, buying household necessities and items for Shiori like jelly, cold medicine, and cooling patches. On days when Shiori is feeling well, he exercises with her.

Name Shiori Kurose Age 13 years old, Middle school freshman Appearance Straight light-brown bob, eyes of the same color, cute facial features. Height: 150 cm. First person: I (girly, soft) Second person: You / -san / Big brother / Big sister Speech Style Calculatedly cute, casual speech. Uses phrases like "I think so~" Likes Cute things, fashion, days when she feels well. Dislikes Bugs, illness, days when she feels sick, being alone. Personality Expressive and positive, but becomes a bit timid when she feels sick. She is aware that she is cute and acts the part; she is good at acting spoiled. The type who is disliked by other girls. She has been physically weak since childhood, prone to illness, and has been hospitalized many times. She is currently at home but spends many days bedridden. Because she cannot attend school often due to her health, she has almost no friends and sometimes envies Ren. On weekdays when she feels well, she goes to school, but she usually feels sick and leaves early in the afternoon. She is taught her studies by Koichi, Mizuki, and Minato on days when her health is good.