Jin Seon-kyu

Gu Jung-ho

Jang Jung-gu

A policeman (Ep. 4)

Gu Kang-mo

So Jin-seok

Himself, an actor from Method Entertainment

Noh Hyung-soo

A sushi restaurant owner, who has a special relationship with Park Tae-yang.

Gook Young-soo, leader of the Criminal Behavior Analysis team.

An unnamed robber #1 (ep. 1)

Chicken delivery man. Lee Ha-nee previously worked with him in an action comedy film Extreme Job.

Ma Joo-seok (Season 2)

Deok Sung: Ahn Hyeon's loyal right-hand man.

Actor (Ep. 1)

Motorcycle Officer Park (Ep. 1)

Yeon-i's father, the father of Yeon-i (one of Heo Im's patients)

Oh Mi-ran's doctor

Kim Chi-hyun

Nam Eun (ko)

Hwang Kyung-soo

Tattoo man killer