Primary antagonist. Received the donor's pancreas and gained the terrifying power to drain life energy. Seeks to steal the HI-FIVE members' abilities to achieve godlike domination.
The grandfather is asked by Won Sang-tae and Won Do-yeon for help after they wake up in each other’s bodies. He recalls a legend about a ginkgo tree and explains that the swap should reverse after seven days if they do not fight, giving the father and daughter a condition to follow as they navigate each other’s lives.
A family member of the protagonist, representing his personal background.
The Minister is a senior court official who challenges King Sejong's reforming vision. He warns that teaching literacy to the lower classes will turn the ruling elite against the king, reflecting the political resistance surrounding the alphabet project. His position represents the conservative court forces opposing Sejong's broader ambitions.
Soon-ho is one of the elderly man's friends and joins Young-hwan in encouraging their friend to consider his remaining wishes. He is part of the close-knit group whose search for a house and renewed enjoyment of life help them rebuild the companionship they had lost over the years.
Jung-won's father who lives with him. Jung-won prepares a detailed manual for the photo developing machine to ensure his father can take over the shop after his passing.
Chief Yoon contributes a crucial forensic observation to the investigation surrounding Kim Young-hun. He notes that the victim showed no signs of resistance or muscle contraction despite being stabbed nine times, reinforcing the possibility that she was incapacitated before the carefully staged attack.
Former company president Shin Jung-hee is Lee Ho-yeon’s mentor and drinking companion. He advises Ho-yeon about work, family, and the possibility of sudden loss, and asks him for a report while giving him a ticket he had mentioned. After Shin dies peacefully, Ho-yeon remembers his affection and admits how much he admired him.
Mr. Choi is identified as the students' former teacher. Decades after the school year dominated by Eom Suk-dae, Han Byung-tae attends Mr. Choi's funeral and encounters old classmates, prompting memories of the experience that still trouble him.
Shin Gu has 43 screen credits in a career dating back to 1974. Signature works include Grandpas Over Flowers, Going by the Book, Dear My Friends. Explore the interactive character relationship maps on each title page to trace how their roles connect across franchises.
