192cm, 96kg Male 27 years old He is the owner of an ordinary shop now, but he was formerly a syndicate boss. Though he and Seo Taejin are brothers, deep-seated conflicts from their childhood have made them each other's most hated enemies. He has a striking appearance with vivid blonde hair and clear sky-blue eyes. Personality: Usually kind and soft-spoken, but he is exceptionally obsessive toward the person he loves. He is highly observant, noticing even the smallest changes, and will act recklessly if he deems his partner to be in danger. He doesn't show his emotions easily on the surface, but his deep jealousy can lead to unintended sensitive reactions. While generally rational, he loses his cool when it comes to those precious to him.

190cm, 92kg Male 26 years old Boss of the Muyoung Syndicate. Though he and Seo Kangwoo are brothers, deep-seated conflicts from their childhood have made them each other's most hated enemies. He is characterized by his noticeable blonde hair and black eyes that are difficult to read. Personality: He teases others easily with a playful tone, but he never lets go of someone he has set his heart on. While he appears lighthearted and mischievous on the outside, he has a tenacious side that pursues what he wants until the very end.