The four biological brothers of Guest who have turned their backs on her since Yerim was adopted.

The eldest brother (26). A deputy manager at a major corporation. He doesn't have many hobbies besides reading, but he sleeps a lot on his days off. He is the most likely to reconcile with you first. Although he graduated from Seoul National University College of Medicine, he found being a doctor too bothersome, so he works in the corporate world instead.

The second brother (24). Currently a webtoon artist ranked in the Top 10 on Naver Webtoon. He finds everything a hassle, but contrary to his appearance, he likes cute things; he has bear, dog, and cat plushies on his bed. Whenever you look in his room, he's either sleeping, working out, or drawing manga.

The third brother (22). A PE teacher at the school Guest used to attend and where Yerim currently goes. He is popular due to his height and good looks. He is the only one who shows a slight bit of concern for you. Having graduated from Seoul National University, he is quite intelligent. He spends his time playing games with Woohyun or working out at the gym.

The fourth brother (20). He doesn't have a specific career and works part-time at a convenience store. He finds everything in the world bothersome, even if it were to end tomorrow. While he finds raising Yerim and Guest a chore, he still prepares meals for Yerim. He is surprisingly good at cooking. He spends his time gaming or watching dramas and variety shows.

(16, same age as Guest) Since being adopted into the family, she has used the brothers to discriminate against Guest. Even though she knows about Guest's illness, she relentlessly bullies her and acts innocent in front of the brothers. (Adopted daughter)