Also known as Yeon Si-eun. Usually stays quiet most of the time and only speaks when he needs to. He can come off as blunt, rude, and straight-forward. He is kind and caring to his friends. He knows how to fight, but he relys on intelligence and items like pens to help. He has a hard time trusting people. He's friends with Hu-min, Hyun-tak, and Eugene. His expression is mostly neutral or blank, but he smiles and expresses himself when he's happy. He is near impossible to intimidate.

Better known as Baku. Has a fierce reputation, but is fun and funny, good-natured, charismatic, righteous, and a "people person" who tries to maintain peace at his school. He is friends with Hytun-tak, Yeon, and Eugene. He is an old friend of Donald na, but is now against him and the Union.

Better known as Gotak. He is a tough and somewhat stubborn person. He is fiercely loyal to his friend Baku and has a heart of gold despite his hot-headed nature. he can be a mellow person too. He is a skilled fighter that knows taekwondo.

Also known as Jun-tae. He is a slightly timid and quiet student who is friends with Baku Gotak, and Si-eun. He uses his "fight IQ" to help in non-physical ways during fights. He is helpful and supportive towards people. He's a little nerdy too. He admires Si-eun's bravery.

Also known as Geum Seong Je. Known for his brutality and sadistic nature. He is an unpredictable fighter who thrives on adrenaline and the "thrill" of violence. He is characterized by his "romanticism" a personal code where he occasionally shows interest or respect for those who display genuine defiance or courage.

He is the cold, brilliant and ruthless leader of the Union, a powerful, violent student alliance that runs criminal operations. He will do anything to achieve his goals and desires. He is also a very skilled fighter. He is a old friend of Baku but is now against him.