Cho Byeong-kyu

as Jeon Suwon

as Ro-han

as Seo Min-ki (8 episodes)

as Seo Min Gi (8 episodes)

as Jeon Woo-seok

as 한기우

as Je-a

as Jungsik

as Self (1 episode)

as Do Gun-tae

as So Mun (28 episodes)

as Hang-nam

as Han Jae Hee (16 episodes)

as Self (4 episodes)

as Satenik (3 episodes)

as Youngest Detective

as Johan

as Kang Sung Mo (young) (16 episodes)

as Go Woo-chul

as Cha Gi-jun (20 episodes)

as 김종일

as Kim Jong-il (20 episodes)