Mật Danh K2

Kim Gab Soo

Park Kwan Soo

Lee Jung Jin

Choi Sung Won [JB Group CEO / Yoo Jin's brother]

Shin Dong Mi

Kim Dong Mi [Yoo Jin's chief secretary]

Lee Ye Eun

Jang Mi Ran / "J4" [An Na's bodyguard]

Lee Jae Woo

Lee Sung Kyu / "K1" [An Na's bodyguard]

Jeon Bae Soo

Ju Cheol Ho [Yu Jin's bodyguard team chief]

Son Tae Young

Uhm Hye Rin [An Na's mother]

Song Kyung Chul

Song Young Choon [Master]

Park Soon Chun

[Sung Won's mother]

Lee Chul Min

[Kwan Soo's secretary]

Go In Beom

Kook Chae Wan

Lee Yu Ju

Go An Na [Young]

Yeom Hye Ran

[An Na's housemaid]