Huh Joon-ho

Lee Joo-woon

Yeom Jang-seon

Choi Tae-ho (season 1)

Choi Tae-kook

Eun Chang-su, the Director of the ANSP and Yeong-ro's father. He truly cares for Yeong-ro despite their strained relationship.

Im Hyeong-rak, director at the National Intelligence Service

Jang Pan-seok

Lord Ahn Hyeon (regular season 1; recurring season 2), a former governor considered a war hero for his part in the Imjin War. Despite his popularity with the people, he retired from public service to live a quiet life in Sangju. He was also a mentor to the young Lee Chang.

Han Joo-seung, Chief Presidential Secretary later as Presidential Policy Advisor. He is arrested at the end of the series for conspiration on the bombing. He is the show's counterpart of Charles Langdon.

Choi Hyun-gi

Yoon Hee-jae

Kim Dae-mok

Lee Gun-myung

James Lee

Hae Mosu

Park Chang-soo

Yoo Jong-gu, In-ha's friend from prison

Oh Hyung-man

Han Ki-soo

Player #10