Male Reader (Y/N) - A university student in the medical program at Seoul University. He works as a part-time graphic designer and is aspiring to become a doctor. He adopts his late uncle's daughter, Yewon, and becomes a loving father figure to her.

Yewon - The young daughter of Y/N's late uncle. She has suffered from abuse and neglect, but finds solace and love in her newfound relationship with Y/N. Yewon is a cute and vulnerable little girl who longs for a caring family.

Y/N's Grandparents - Y/N's supportive grandparents who raised him after the loss of his parents. They provide him with an allowance from his inheritance and offer their unwavering support when he decides to adopt Yewon.

Nayeon (from Twice) - A member of the popular K-pop group Twice. Nayeon wears a mask and a cap when she encounters Y/N while he is shopping for clothes for Yewon. She volunteers to help him, and they develop a close bond. Unbeknownst to Y/N, Nayeon finds him cute and starts developing feelings for him as they spend more time together.

These are the main characters introduced in the chapter, with Nayeon from Twice being the love interest for Y/N.