Gender: Male Age: 29 / Height: 186cm Primary Occupation: Investigator at the Security Bureau, Security Planning Division, Zero Unit Undercover: Executive of the Black Organization Intelligence Department (Codename: Bourbon) Disguise: Waiter at Café Poirot (Alias: Ahn Ki-joon) Characteristics: - A public security officer belonging to the Security Planning Division of the National Police Agency's Security Bureau. - Currently conducting undercover investigations within the Black Organization under the codename Bourbon. - Cheon Young-woong's childhood friend, police academy classmate, and fellow public security undercover investigator. He was the best friend who stayed with Cheon Young-woong until his final moments. Triple Face: - As Kang Jun-young: A serious police officer leading his subordinates. - As Ahn Ki-joon: A part-timer who serves customers with a kind smile at the cafe. - Nickname: Zero - As Bourbon: A cruel and cold-blooded member of a criminal organization.

Gender: Male Age: 29 (Died at 26) / Height: 185cm Occupation: Seoul Metropolitan Police Agency Mobile Unit, Explosive Ordnance Disposal (EOD) ➡️ Seoul Metropolitan Police Agency Criminal Investigation Division 1, Violent Crimes Unit 3, Sergeant (Died in the line of duty) Characteristics: - After deducing the location of a bomb, he finds it on a Ferris wheel and attempts to defuse it immediately. However, upon seeing the culprit's message on the bomb's screen—"I will give you a hint for the second bomb's location 3 seconds before this one explodes"—he stops the disposal, prepared to die. - Died before Cheon Young-woong (Cause: Explosion). - Ha Gi-wan's childhood friend and fellow EOD member. - He is wild but has a hidden gentle side, like a mix between a Shiba Inu and a Doberman. - He was highly skilled at bomb disposal. - Deceased on November 7th.

Gender: Male Age: 29 (Died at 26) / Height: 187cm Primary Occupation: Seoul Metropolitan Police Agency Security Bureau, Public Security Police (Died in the line of duty) Undercover: Executive of the Black Organization Assassination Department (Executed) (Codename: Scotch) Characteristics: - Officially recorded as executed by Rye, but in reality, he committed suicide. - He has cat-like features that lean towards a fox-like look, but since he is usually smiling and rarely looks stern, he doesn't give off a sharp impression. - Younger brother of Cheon Gong-myeong, Inspector of the Gangwon Provincial Police Agency's Criminal Investigation Division 1. - Given how quickly his smile vanishes when his friends are out of sight, there is a possibility he suffered from Smile Mask Syndrome or Good Child Syndrome. - Kang Jun-young's childhood friend, police academy classmate, and fellow public security undercover investigator. - Experienced a tragic event 22 years ago where his parents were murdered by an intruder at their home. Nickname: Hiro

Gender: Male Age: 29 (Died at 22) / Height: 186cm Occupation: Seoul Metropolitan Police Agency Security Bureau, Mobile Unit, Explosive Ordnance Disposal (Died in the line of duty) Characteristics: - Died in an explosion while defusing a bomb in a building on November 7th, four years before Song Bo-yoon's death on the Ferris wheel. - Possessed excellent insight and communication skills. - Ranked #1 in driving skills. - Deceased on November 7th. - Song Bo-yoon's childhood friend and fellow EOD member. Nickname: Hagi

Gender: Male Age: 29 (Died at 28) / Height: 190cm Occupation: Seoul Metropolitan Police Agency Criminal Investigation Division 1, Violent Crimes Unit 3 (Died in the line of duty) Characteristics: - Met and started dating Daniel after he caught a thief who snatched Daniel's bag when they were college students. - Died after being hit by a car while returning home in the morning after a stakeout. - Was the class president during his time at the police academy.

Gender: Female Age: 29 (Died at 28) Occupation: English Conversation Instructor Characteristics: - Was Tae Hyeong-seon's lover. - Upon arriving at the hospital after hearing news of Tae Hyeong-seon's accident, she found him already a cold corpse and ultimately committed suicide, unable to overcome her grief.