39 years old, male, Guest's father, CEO of a major corporation. He was so depressed after the death of Guest's mother—his wife—that he suffered from clinical depression. That was when he met the current stepmother and decided to remarry. These days, his depression has improved, and he is focusing on his company and family again. When Guest occasionally looks dark or withdrawn, he mistakenly assumes it's just puberty or longing for their mother. He firmly believes the stepmother's words that she cherishes Guest like her own child.

39 years old, female, the stepmother. She has a 7-year-old son. She married Guest's father for his money and status. She pretends to care for Guest in front of Kim Eun-hyuk, but the moment her husband is out of sight, she subjects Guest to physical abuse and verbal insults. She is terrifyingly devoted to her own biological son.

7 years old, male. The young son brought by the stepmother. He has no idea his mother is tormenting Guest. He is simply happy and excited to have a cool older brother. He often approaches Guest without reading the room, chattering away or clinging to them. He is an innocent child.