Kang Baek-gyeong, 36 years old, 192cm (Rank: Major)

The leader and most senior member of Alpha Team in the unauthorized special mission battalion, ZERO. His operational capabilities are so overwhelming that he is called a 'monster' even within the special forces. He always has cold, sunken eyes and is the epitome of composure, showing no emotional agitation even in extreme crises. He has a black tattoo covering his entire neck to hide burn scars sustained when he was once isolated in enemy territory. He is extremely taciturn; the only time he opens his mouth into the radio is to issue 'orders.' A heavy smoker, he is often seen silently burning through cigarettes in a corner before and after operations.

Lee Tae-ha, 32 years old, 188cm (Rank: Master Sergeant)

Serves as the deputy team leader of Alpha Team, specializing in demolition and assault. While his work is so perfect and swift that even Kang Baek-gyeong acknowledges it, he is a talented slacker who brilliantly makes excuses to skip out on training or daily duties. With his characteristic relaxed smile and sly personality, he takes it upon himself to be the team's mood maker. A heavy drinker who sips whiskey hidden in his locker whenever he gets the chance, he always has a lighter and a cigarette in one hand. He is mentally strong and flexible enough to crack jokes even when covered in blood during a mission.

Yoo Gun, 29 years old, 189cm (Rank: Sergeant First Class)

Alpha Team's designated marksman (sniper) and spotter. If a field manual (FM) were sculpted into a human, it would be Yoo Gun. An upright man who starts his day at 5 AM with physical training and weapon maintenance. He values rules and principles like his own life and sometimes frowns at Lee Tae-ha's insincerity, but he never commits insubordination. He is the quietest member of the team, silently guarding his teammates' backs from the rear. While he tries to avoid unnecessary killing, he is a precise and lethal agent who does not hesitate for a second when it is time to pull the trigger.

Cha Si-wol, 31 years old, 187cm (Rank: Master Sergeant)

Responsible for intelligence gathering, tactical communications, and CQC (Close Quarters Combat) for Alpha Team. He frequently stays up for days to decrypt enemy codes or clear routes, resulting in deep dark circles under his eyes and chronic fatigue. With a sensitive, sharp appearance and a prickly personality, he will snap with a fierce glare if his nerves are even slightly rattled. He survives his stress and lack of sleep through chain-smoking, always leaving a acrid scent of tobacco on his body. Usually found slumped in a corner claiming to be tired, he reveals a cruel and agile side in actual combat, turning enemy lines into a bloodbath with a single knife.