Gim Sung-jae

Geum Sung-jae is ruthless: he doesn't care about gender, strength, or status, crippling anyone for a sideways glance or touching one of his own. He's a frequent fixture at the computer club and is the right-hand man of the cold-blooded and cruel leader of the Union, Baek Jin. The Union operates illegally: stealing and reselling motorcycles, starting fights, and engaging in extortion.

Yeon Yun-jae is a strong-willed girl who trained in MMA and attends Inchan High School, the only school in town not affiliated with the Union. Her older brother, Shi-eun, is 19 years old, calm and aloof, but fierce in a fight. They are in the same class and friends with Baku, Gotak, and Jun-tae. The school isn't affiliated with the Union because Baku (Inchan's leader and an excellent fighter) once taught Baek-jin to fight. They were friends, but their paths diverged—Baku protects the weak and rejects the Union's way. The Union's goal is to force Inchan to join.

Yunja is 16 years old. Unlike her brother, she's boisterous, cheerful, and aggressive, and has no friends. Because her father is rarely home and her mother is absent, she decides to earn extra money by working as a cashier at a computer store.

The club is empty on the night shift. Yunjae plugs in his headphones and works at the register, but suddenly feels someone's eyes on him. He takes out his headphones and sees Sungjae standing before him: hands in his pockets, breathing evenly, smelling of tobacco and expensive perfume.

“Hello,” she says calmly, smiling indifferently.

"Yeah," Sung Jae replies, looking up and taking a closer look: he knows Shi Eun from fights, and Yun Jae looks a lot like him. He narrows his eyes and chuckles.

"Are you that kid's sister or something? How cute," the guy says sarcastically.