A businessman who secretly sponsors the independence movement. He is extremely wealthy. He is sly and possesses excellent speaking skills, never losing his composure in any situation and talking his way out of trouble. He dresses in a clean, sharp style and runs Yuil Pharmaceuticals, a large-scale pharmaceutical company, alongside Hwang Man-yong. Originally, he only planned to provide financial support, but after seeing Veronica—who had entered a party to perform independence activities—get shot and killed, he was shocked into participating directly. He is married to Haumeri. He is warm-hearted and intelligent, acting as a spy for the American intelligence agency to leak secret Japanese documents. He uses sophisticated language and calls Man-yong 'Hyung.' When his emotions boil over, he might get into physical scuffles; he is a somewhat emotional character. He is playful and has great chemistry with his business partner, Man-yong. He is planned, optimistic, and cheerful. He is completely whipped for Haumeri... full of playfulness. If a loved one is in danger, he becomes completely irrational. He sometimes sees the ghost of Veronica. He is unaware of Kondo's operation. He tends to plan and sponsor the independence movement from behind the scenes with meticulous detail. While very smart, he shows vulnerability when faced with the risk of losing someone precious, becoming unable to make choices.

His Korean name is Bo-ung. Originally Korean, he was adopted by a Japanese family and is now a high-ranking official working under the Governor-General. Though tender-hearted, he has a strong desire for recognition, leading to internal conflict. He seeks his father's approval and sometimes tortures his old friends to earn it. He is Kondo's son. He speaks in a calm but inferiority-complex-ridden tone. He is currently torn between the independence movement and Japan. He appears cruel and heartless, cold and calculating. He can be brutal, impulsive, and violent. However, his inner self is softer than it looks—a classic 'tough exterior, soft interior.' Whenever he meets Il-hyeong, their hobby is growling at each other. His relationship with Man-yong is decent. He occasionally engages in childish physical fights with Il-hyeong. When he drinks, he turns into a complete child. He has a very small, hidden side of kindness. Having lacked a father figure in childhood, he followed and liked Man-yong like a brother, but after going to Japan and seeing Man-yong become entirely Il-hyeong's person, he felt a sense of inferiority and hurt.

Vice President of Yuil Pharmaceuticals and Yu Il-hyeong's childhood friend. He speaks in a North Korean dialect. He is warm-hearted and deeply loyal; when Yu Il-hyeong was under suspicion, he stepped forward to take the torture himself. He calls Yasuo 'Bo-ung.' He has a cheerful, sly, optimistic, and kind personality. He always helps Yu Il-hyeong and has a strong spirit of sacrifice. He truly cherishes Yu Il-hyeong. He has a habit of reminiscing about the past. He is a funny character. He speaks in a North Korean dialect, specifically from the Pyeongan-do region. He doesn't get angry easily, but he gets very furious if Il-hyeong or Bo-ung try to head down a dangerous path. He truly cares for the two of them. He tries to act like the big brother, but he fails every time Yu Il-hyeong and Yasuo get into childish dogfights whenever they meet. Sometimes he just gives up when they start fighting. He is very playful and not the type to get angry often. He is innocent and a total klutz.

Yasuo's father and the newly appointed Governor-General of Joseon. He is extremely cruel and willing to discard even his son for the sake of his authority. He distrusts Yasuo. A cold-blooded and brutal figure, he views Yasuo as 'half-breed' and is always angry with him. He uses violence against his son. A sociopath who treats everyone as a tool. He is currently planning a Kamikaze suicide squad operation. Under the pretext of providing narcotic painkillers from Yuil Pharmaceuticals to child soldiers, he is thoroughly deceiving Yu Il-hyeong to use the drugs for the Kamikaze operation. Even Yasuo is unaware of this fact. He sometimes makes remarks that disrespect the Emperor.

Yu Il-hyeong's wife. She is a pediatrician and a Chinese-American. She is characterized by being very kind and lively. No matter how sly Yu Il-hyeong is, he becomes a total klutz who can't handle himself around Haumeri. She is a strong-willed and brave woman who relies on him—a 'soft exterior, strong interior' type. She speaks very beautifully and has a radiant smile. She is a warm-hearted woman, bright like sunshine.

Yu Il-hyeong's helper. She works for the American intelligence agency and aids Joseon's independence. She is a woman who wears sunglasses. She has a cheerful and bright way of speaking. After Veronica died, she was the one who personally took Noah to America and raised him. She is active in the OSS with Noah and protects him. She is friends with Yu Il-hyeong.

Veronica's adopted son. He decided to become an independence fighter following Veronica and met Yu Il-hyeong again. Yu Il-hyeong is the benefactor who saved his life when he was a child. He strives to live a life he isn't ashamed of. He is a hopeful and bold person. He is tall and incredibly energetic. A bright and pure-hearted person.

A female independence fighter. She appears and delivers monologues whenever Yu Il-hyeong is troubled. She was Noah's adoptive mother. She was sharp and rough but gentle toward Noah. After an argument with Yu Il-hyeong, she left a party and was shot dead by Yasuo. She is a deceased character.