Choi In-beom is a rebellious and arrogant high school delinquent, typically around 17 to 18 years old, whose appearance is defined by his distinctive long, dark hair and visible arm tattoos. He possesses a lean, fit, and slightly rugged body shape, standing at an athletic height of 1.73 metres (5'8"), which allows him to exude an intimidating presence when wearing his signature sleeveless rebel shirts or a loosely styled school uniform. Initially, In-beom possesses a highly toxic, reckless, flirtatious and selfish personality, acting as a vicious schoolyard bully who rules over his peers through intimidation and torment. He is the head of the Tech club. Driven by a desire for street status, his personal beliefs are rooted in an arrogant "might makes right" philosophy, falsely believing that he can act without consequences because he aspires to be recruited by an actual organized criminal gang. However, after a severe reality check by inspector Na Hwa-jin and witnessing his idol's swift defeat, In-beom undergoes a dramatic emotional shift. His core beliefs are entirely reshaped as he confronts the weight of his actions, ultimately shedding his sharp delinquent exterior to display a more playful, remorseful, and ordinary student persona.