Hidden Identity

Composer

• 
  Kim Jang Woo

Director

• 
  Kim Jung Min

Editor

• 
  Steve M. Choe

Martial Arts Director

• 
  Baek Kyung Chan

Screenwriter

• 
  Kang Hyun Sung

Main Role

• 
  Kim Bum

  Cha Geon Woo

  Main Role
• 
  Park Sung Woong

  Jang Moo Won

  Main Role
• 
  Yoon So Yi

  Jang Min Joo

  Main Role
• 
  Lee Won Jong

  Choi Tae Pyung

  Main Role

Support Role

• 
  Kim Tae Hoon

  Min Tae In

  Support Role
• 
  Lim Hyun Sung

  Jin Deok Hoo

  Support Role
• 
  Im Jong Yun

  Han Sang Joon

  Support Role
• 
  Kim Min Joon

  Teacher Jung

  Support Role
• 
  Lee Kyung Young

  Choi Dae Han

  Support Role
• 
  Kang Sung Jin

  Nam In Ho

  Support Role
• 
  Choi Jung Woo

  President Lee [President of arms manufacturing company]

  Support Role
• 
  Kwon Hae Sung

  Choi Myung Shik

  Support Role
• 
  Lee Ju Eun

  Ha Yun Mi [Princess mermaid]

  Support Role
• 
  Kim Byung Chun

  Ma Sang Wook

  Support Role
• 
  Oh Dae Hwan

  Lee Moo Sung

  Support Role
• 
  Im Kang Sung

  Yoo Jin Woo

  Support Role
• 
  Heo Jae Ho

  Jung Sang Joon [Head of a department]

  Support Role
• 
  Jo Yeong Jin

  Lee Il Han [Chief of the National Police Agency]

  Support Role
• 
  Park Sung Taek

  Park Sung Mo

  Support Role
• 
  Yoo Sang Jae

  Choi Chul Han

  Support Role
• 
  Tae Hang Ho

  Seung Gyun [Bodyguard]

  Support Role
• 
  Hwang Sung Joon

  Park Chung Shik

  Support Role
• 
  Hong Sang Jin

  Jo Chul Joong

  Support Role
• 
  Lina

  Kim Mi Jung

  Support Role
• 
  Lee Soo Yong

  Ryu Tae Shik

  Support Role
• 
  Ahn Ji Hyeon

  So Yeon

  Support Role

Guest Role

• 
  Jung Jin

  Chang Min [Geon Woo's partner] (Ep. 1)

  Guest Role
• 
  Lee Min Ji

  Yun Soo [Patient] (Ep. 6)

  Guest Role
• 
  Seo Yoo Jung

  Eom In Kyung (Ep. 11-12)

  Guest Role
• 
  Kim Hye Yoon

  Jang Min Ju [Young] (Ep. 14)

  Guest Role
• 
  Kim Ji Won

  Min Tae Hee [Min Tae In's sister]

  Guest Role
• 
  Kim Ha Rin

  Yun Hwa [Teacher Jung's wife]

  Guest Role
• 
  Jang Seo Hee

  Ji Won [Teacher Jung's daughter] (Ep. 3)

  Guest Role
• 
  Uhm Soo Jung

  Park Min Young [Prosecutor]

  Guest Role
• 
  Song Yong Tae

  Yoo Dong Joon

  Guest Role
• 
  Yang Lei

  Du Yun

  Guest Role
• 
  Ryu Seong Hyeon

  Professional Baek [100%]

  Guest Role
• 
  Seo Kwang Jae

  Jo Se Young [Disease Control Center Director]

  Guest Role
• 
  Yoon Jong Won

  [Ghost crew]

  Guest Role
• 
  Geum Kwang San

  [Kim Se Jin's gang]

  Guest Role
• 
  Jung Sung Il

  [Um In Gyeong's assistant]

  Guest Role
• 
  Kim Woo Rin

  [Secret agent from Criminal investigation section]

  Guest Role
• 
  Kim Gwang In Guest Role
• 
  In Sung Ho Guest Role
• 
  Jung Jong Woo Guest Role
• 
  Woo Jung Kook Guest Role
• 
  Han Yeo Wool Guest Role
• 
  Park Young Soo Guest Role
• 
  Go Yoon Hoo Guest Role
• 
  Seo Eun Ah Guest Role
• 
  Keum Dong Hyun Guest Role
• 
  Hong Seung Jin Guest Role
• 
  Lee Tae Hyung Guest Role
• 
  Hwang Min Ho Guest Role
• 
  Park Min I Guest Role
• 
  Ham Jin Sung

  [Lee Myung Joo's subordinate]

  Guest Role

Unknown

• 
  Ji Gun Woo Unknown
• 
  Jang Hyun Jung Unknown