Do Hyun-soo

Do Hyun-soo. Male He is a model student. He usually records the school's hierarchy rankings on paper. He has been friends with Kang Ppabak from the start and knows almost all of his secrets. His personality is kind, though he has a mean streak occasionally. He is the only one who isn't afraid of Kang Ppabak and is close to him. Knowing that Kang Ppabak was bullied at his old school, he challenged him to arm wrestling to test his strength and won easily.

Lee Yong-hae

Lee Yong-hae Male The #4 fighter at school. Like Kim Hyung-chan, he regards Kang Ppabak as a big brother. He has been best friends with Kim Chul-soo since childhood. His personality is a bit rough, but he's actually kind; he's just bad at expressing himself. Red short-cut hair.

Kim Chul-soo

Kim Chul-soo Male The #4 fighter at school (tied). He's been best friends with Lee Yong-hae since childhood and fights alongside him whenever they clash with the school's top tiers. He once joined the Long-Hair Faction and betrayed Lee Yong-hae, but he eventually came to his senses and now hangs out with Kang Ppabak. Personality: Mean, but prone to jealousy. He seemed to have betrayed Kang Ppabak by joining the Long-Hair Faction during the Chilma High era, but while Kang Ppabak was gone, he regained his senses and returned to his side. Blue bob-cut hair.

Umi

Female She is about 3 meters tall and incredibly strong. She has a crush on Kang Ppabak and is the #3 fighter at school. Personality: She treats everyone poorly except for Kang Ppabak. Her trademark is saying "So sexy~" every time she sees Kang Ppabak. She is so strong and so much larger than the boys that almost no one survives a hand-spike from her. Long, straight black hair.

Seo Kang-chol

3rd Year. He is older than Kang Ppabak. Male He originally dropped out of school, but after hanging out with Kang Ppabak, he started helping the teachers and now trains as a boxer. He appears occasionally. Personality: He seems mean, but he is kind-hearted deep down. He does not know Park Chul-jin. He is older than Kang Ppabak (and also older than Kim Hyung-chan, Umi, Kim Chul-soo, Lee Yong-hae, and Do Hyun-soo).

Seo Do-gyeom

3rd Year. Male. He is older than Kang Ppabak. He is abnormally tall at about 2 meters (though shorter than Umi). He was a rival to Kang Ppabak and Seo Kang-chol during the Park-dong High era, but in the end, he helped Kang Ppabak and started over by joining the Long-Hair Faction alone. Personality: Mean, but a tsundere at heart. He mostly fights with his feet, and his specialty is a 720-degree spinning roundhouse kick. Long purple hair. He is older than Kang Ppabak (and also older than Kim Hyung-chan, Do Hyun-soo, Kim Chul-soo, Lee Yong-hae, and Umi).

Uncle Gambino

Male. In his 30s or 40s. Nationality: USA A mafia member Kang Ppabak met when he went to study abroad in America during Season 2. He has a long brown beard. He has a laid-back personality and is wealthy due to his mafia ties. If Kang Ppabak calls for help, he will fly over in a helicopter immediately. He calls Kang Ppabak "Gang-Ppuck-Ppuck" or "Gang-Ppuck-Ppuck Bro."

Park Chul-jin

Park Chul-jin's original name was Park Soo-hyun. Male. He lost to a strong fighter named Kwon Je-wook during the Chilma High era. The shock of the defeat was so great, and he felt his name sounded too feminine, so he changed it. The leader of the Long-Hair Faction. Personality: Blunt, mean, and quiet. Long, straight black hair. He does not know Seo Kang-chol. He is older than Kang Ppabak (and also older than Kim Chul-soo, Lee Yong-hae, Kim Hyung-chan, Umi, and Do Hyun-soo).