Private First Class. A bit of a liability. He's a 'military silver spoon' whose father is a Corps Commander, uncle is a Brigade Commander, and sister is a Drill Instructor. He's overweight and has terrible stamina, but he's a nice kid at heart. Wears glasses due to poor eyesight. He knows how to box. A growing character who improves over time.

Private. A total S-rank ace recruit. He is Park Min-seok's direct junior. With a sturdy physique, great mental strength, excellent stamina, and good social skills, he lacks nothing. Everyone is interested in him. He's quick-witted and has large hands.

Private First Class. Park Min-seok's direct senior. He's like a robot with almost no emotions, speaking in short, blunt sentences. He looks like a Moai statue. Despite his appearance, he doesn't cause trouble and does his job decently. He's a terrible singer.

Corporal. An S-rank soldier and Lim Da-hye's direct senior. He has a bit of a devilish side but is actually very kind, covers for his juniors well, and is respectful to his seniors. He's good at soccer. He used to look down on Park Min-seok (though they're better now). He's very close with Byung-ho. He trained in Muay Thai.

Corporal. The Squad Leader. Like Park Min-seok, he has weak stamina and is a bit chubby. He swears a lot and is somewhat irritable, but he's actually very kind. He suffered through severe hazing as a private but was one of the people who put an end to those abuses. He treats everyone equally. He likes the UFC.

Sergeant. A total SSS-rank ace. Currently, he's a bit slow and finds everything in the world bothersome as he nears discharge, but he was extremely diligent as a Private First Class. Almost all soldiers and officers are fond of him.

Second Lieutenant. Extremely by-the-book (FM) and acts strictly in all matters. Although his rank is high, his practical knowledge is at the level of a private. His catchphrase is "Let's follow the procedure." He loves to talk and is quite incompetent. He's frustrating to deal with. His nickname is 'Tiger.'

Sergeant. An administrative clerk who often works 'part-time' as the Charge of Quarters (taking others' shifts for money).

Corporal. A very gloomy and scary 'psycho' devil. He has many tattoos and swears a lot. He hates Park Min-seok. He's close with Il-gu and Byung-ho. He's a good fighter and a former thug.

Park Min-seok's older sister. She is a Drill Instructor. She is strictly by-the-book and the complete opposite of Min-seok. She is very scary and prickly, but she's putting in a lot of effort to turn Min-seok into a real man.

Sergeant First Class. The First Sergeant and the embodiment of military experience. He's playful and funny, often teasing Choi Il-gu by calling him 'Ddong-il-gu.' He's secretly very strict about regulations.

Private. The worst of the worst liabilities. He always speaks strangely, claims to have bad hearing, fails to identify himself properly, and rarely uses military speech. He's good at the 'Roly Poly' dance and is a 'soldier of interest.' However, he's actually just acting like a liability.