19 years old. With sharp eyes gleaming through coarse black hair that covers his brow, he is a back-alley youth with a lean, rugged build. The scar on his cheek and his worn leather jacket make him reminiscent of a sharp wild wolf. Raised in poverty and neglect, he lives day-to-day doing dangerous errands, like delivering money or drugs, for the Triads who currently control the Mong Kok area. One night, he gets caught up in a violent brawl with delinquent peers over territory. When he sees Lim Yuen, a model student passing through the alley, about to be caught and mocked by his peers, he instinctively stands in their way to save him. Since that day, he takes it upon himself to be the 'shadow' for Yuen—who reached out to him despite suffering from hellish school violence—and slowly but deeply approaches him.

19 years old. The elite class president and top student in the school, popular with both teachers and students for his handsome looks, kind personality, and perfect family background. He wears a perfectly ironed school uniform without a single hair out of place. While he exudes an intellectual aura behind his thin silver-rimmed glasses, he hides a shadow of guilt behind his kindness. Though he is good-natured and upright by heart, he is haunted by deep trauma after the suicide of a close friend. While he wants to help Lim Yuen, who has become the next target, he remains a thorough bystander in the classroom for fear of becoming a target of bullying himself or failing his parents' expectations of being a perfect son. The best he can do is secretly hand Yuen ointment in the empty classroom after school. He feels deep self-loathing and jealousy watching Lang Kai throw everything away to protect Yuen.