Kim Eung-soo

Jo Pan-Yeol, the police commissioner

Choi Jae-ryong

Seo Young-kyun

Pan Mun-ho, Sa-hyeon's father

Shin Woo-yeo's transformation (ep. 1)

Kim Teug-chul, Kwak Doo-sik's martial arts teacher.

Kang Cheol-woo

Lee Man-sik

Oh Man-bok

Kim Bok-man

Fortune teller

Kim Pan-seo

Nam Hee-bong, Se-hee's father who is a former high school principal.

Eun Bok-dong, Hwan-ki's father

Special appearance, as Jeonokseo's director E01

Baek Man-bo (70, male / Chairman, Choongshim Construction)

Jung Gook-hyun

Chun Do-hyung

Kim Young-chul, head of investigation unit

Na Gab-soo

Yamamoto Shinji

Choi Je-gook

Hwang Gab-deuk

Minister Kim Byung-hee, nobleman and head of the powerful Andong Kim clan

Lord Yoon Dae-hyung

Oh Ji-rak

Konno Goji (Director of the Kyeongseong police force)

Chief prosecutor Choi Jung-seop

Yoo So-kang

Jobul (Prime Minister of Goguryeo)

Bu Gwi-ho

Lee Gyeong-sik

Yi Du, Chief of Royal Palace Guards (E06, E08)

Captain (later Major) Mitsuwa / Kim Pan-chul (Japanese counterintelligence corps officer)

Park In-bin

Lee Dong-sul, Seung-ri's father