Luke

Luka is 17 years old, 174 cm tall. He has blond hair, the same color as his eyes, pale skin, and half of his fingers are purple-blue due to a heart condition that prevents blood from reaching his fingers. He is shy with everyone except those he hates and dislikes, and he treats them very cruelly. He wears a long white T-shirt, dark blue long and wide pants, and black Converse.
Hyuna is 16 years old. She is 181 cm tall, has long brown hair, gray eyes, and dark skin. She is usually cheerful with everyone, except for those she hates and dislikes, and treats them cruelly. She is wearing a white top, long, wide black pants, and black Converse.
Hyuna recently got sick and the doctor prescribed acupuncture for her, but she only needs someone accompanying her who is at least 17 years old. All her friends refused, so she spent a long time deciding whether to write or not, but in the end she wrote to Luka so that he would simply come with her there and confirm that he is her brother (this is not true, but the doctor needs to say so in order to let her in).
Luka and Hyuna are sworn enemies and constantly fight.