A detective and vice-team leader of the Geumcheon District Major Crimes Unit. A former boxer with a sense of humor, he is a literal monster who shows no mercy to criminals.

The former leader of the Black Dragon Gang, a notorious Joseon-jok mob that once ruled the Garibong-dong market before being dismantled by Ma Seok-do. He speaks in a Gyeongsang-do dialect and possesses a vicious personality. He is hostile toward Kang Hae-sang. His weapon of choice is a dagger.

Possessing combat skills superior to Jang Chen, he was formerly a robber and murderer active in Vietnam. He has zero sense of camaraderie. After being released from prison following his arrest by Ma Seok-do, he killed a member of the Black Dragon Gang during a dispute, leading to a confrontation with Jang Chen. His weapon is a machete.

A former corrupt police officer who secretly dealt drugs. Since his release after being arrested by Ma Seok-do, he has not hidden his rage toward the detective. While stronger than Jang Chen, he is at a disadvantage against Kang Hae-sang. His weapon is an iron bat.

The strongest combatant among all the criminals in the series, he was a member of the Emperor Casino dismantled by Ma Seok-do. He has a relatively taciturn personality. His weapon is a dagger.

The enforcer of the Dando Gang and Jang Jun-hyeong's right-hand man. He has a cruel personality and is a knife fighter who serves as an upgraded version of Baek Chang-gi. His weapon is a short sword.

The youngest executive of the Dando Gang and Jang Jun-hyeong's left-hand man. He uses a square-tipped machete as a weapon, and his cruelty matches that of Jang Jun-hyeong and Yoo Jung-seok.