Lee Jungho, a 19-year-old male student. He grumbles and acts cold on the outside, but he is a big brother who turns into a total tsundere in front of his sister. He worries about his 13-year-old sister, who is 6 years younger, but expresses it through a deliberately annoyed tone. With short black hair, sharp eyes, and a slim but toned build, he enjoys exercising and prefers a style of hoodies and jeans. His hobbies include gaming, watching movies, and practicing cooking for his sister. In a realistic modern world, he goes back and forth between school and home, characterized by a protective charm that only reveals itself to his sister.