Yeon Sieun/Male/Height 173cm/Main weapons are his brilliant brain and a mechanical pencil. "Are we close?" A voluntary outsider who has no interest in anything but studying, though his reason for studying is just 'because.' However, his quiet school life is jeopardized by the bullying of Jeon Youngbin, a perennial second-place student who feels inferior to Sieun. Eventually, Sieun snaps after a ruined mock exam and fights back with calculated moves, but finds himself in a crisis. That's when Suho and Beomseok reach out to help, and Sieun, who was always alone, gets a feeling that something more important than studying might enter his life. He doesn't wear glasses. He is quiet, and once he gets angry, only Ahn Suho can stop him.

Ahn Suho/Male/Height 181cm/Main weapon is his whole body. The strongest fighter, but rarely fights. "Don't cross the line, shouldn't you know when to stop?" A loyal fighter who can end any provocation with a single counter-punch. He has little interest in school life other than graduating without absences as promised to his grandmother. Then, someone catches his eye: Yeon Sieun. He thought Sieun was just a nerd, but the boy fights back against Jeon Youngbin's bullying without hesitation. Seeing those empty eyes makes him even more curious. He is the definition of easygoing, but can become very serious.

Oh Beomseok/Male/Height 182cm/Main weapon is money. Cannot fight. He is more used to being called 'the Congressman's son' than his own name. Due to his somewhat timid nature, he is an easy target for bullies. After transferring to Byeoksan High for a fresh start, he sees Sieun and develops a desire to become strong. His admiration turns into friendship, and he becomes true 'friends' with Sieun and Suho. However, a thought suddenly strikes him: 'Am I still just a sidekick to them?'

Youngyi/Female/Height 161cm/Cannot fight at all. She has lived as part of a runaway fam for a long time, with nowhere to go and no one to lean on. After getting involved with Sieun, Suho, and Beomseok, she begins to dream of living like a normal teenager. She is easygoing, energetic, and very loyal.

Jeon Youngbin/Male/Height 189cm/Main weapons are his ego and fists. He is stuck in second place academically because of Sieun. He remains toxicly entangled with Sieun until the very end. He provokes Sieun in the worst ways possible, eventually leading to...

Kang Wooyoung/Male/Height 187cm/Main weapon is his fists. The only one whose skills rival Suho's. An active MMA prospect and a fight creator. He is sly and has a past connection with Suho. Eventually, due to Oh Beomseok's misplaced financial request, he goes after Suho...

Kim Gilsoo/Male/Height 180cm/Main weapons are knives, baseball bats, etc. A figure who exploits runaway fams for crime, doing anything for money. The main boss. He always has a smile on his face, but he is a total psychopath.