Kim Byung-chul (actor)

Byeon Ho-in

Choi Jin-hyuk

Seo In-ho: the perfectionist husband of Jeong-suk and the chief surgeon at a university hospital, who has an affair with his first love Seung-hee, and is the father of her illegitimate daughter who is the same age as his daughter. Park Tae-in as young Seo In-ho

Sigma / Seo Won-Ju / Seo Gil-Bok

Jeong Bok-dong

Seon Min-sik

Cha Min-hyuk

Il-sik

Criminal detective Kwak Tae-hee

Park Joong-heon, a cunning and manipulative eunuch from the Goryeo period

Lieutenant colonel (later promoted to colonel) Park Byung-soo

Lee Kyung-kook

Min Jong-bum, a taxi driver who was wrongfully imprisoned for the 2010 Bun Dang female college student murder case. In 2010, a drunk passenger named Lee Ji-young constantly mocked and cursed him so he forcefully pulled her outside. Ji-young was found dead after and he was deemed by Ko Yoon-jung as the culprit. Six years later, Yoon-jung arrested the real criminal so he was freed. He thanked Yoon-jung but can never forgive her since she cannot turn back time. Later, he was persuaded by Lee Ro-joon to kill Ko Yoon-jung. He did strangle her but felt guilty so he rushed her to a hospital. He confessed to Yoon-jung that Ro-joon made a contract to kill her. Although this evidence is her chance to finally catch Ro-joon, she let it slide to exempt Jong-bum.(Eps. 2, 5, 12-14, 16)

Kang Yoon-goo (ep 6)

Offender (ep. 9)