Live action TV
Description
Seol Jin-hee is the younger sister of the series' key character, Seol Kang-woo. Her role in the story is defined by a tragic event that serves as a primary motivation for her brother's actions. Jin-hee is a young woman who helps run a family store and appears to take on significant responsibilities at home. She cares for her older sister, Kyung-hee, who is ailing and has been like a mother to Jin-hee and her brother.

Jin-hee is practical and determined, especially when it comes to her sister's health. She is shown insisting on taking Kyung-hee to a doctor for an MRI despite her sister's protests and the influence of a pastor from a local church. Jin-hee displays skepticism towards the pastor's reliance on prayer, questioning the practical benefits of such an approach over medical treatment. Concern for her family is her primary motivation, leading her into a dangerous confrontation.

The critical event that shapes her place in the narrative occurs when Jin-hee returns home from work one night. Unbeknownst to her, her sister Kyung-hee and the pastor, Hyuk-ju, are both parasites. When she announces her plan to take Kyung-hee to a hospital, the situation turns violent. Her sister's head splits open to reveal the parasite controlling her body, which immediately attacks Jin-hee. Jin-hee attempts to flee, releasing the family dog to save it, but is hunted down and cornered in a tunnel by the group of parasites, where she is killed.

Jin-hee's most important relationship is with her brother, Kang-woo. Before her death, she contacted his friend, Ki-seok, trying to locate him. She also managed to send Kang-woo a truncated message via a messenger app, which reads, "Don't come home no matter--". This final, incomplete warning is discovered by Kang-woo weeks later, filling him with guilt and solidifying his resolve to fight against the parasites that killed his sister. Jin-hee does not have any notable abilities related to fighting parasites and does not undergo character development, as her death occurs in a flashback early in the story's timeline.