Lee Hee-joon

Song Chon

Himself, an actor from Method Entertainment

Lee Joong-yeob, a surgeon

An unnamed robber #2 (ep. 1)

Ko Moo-chi, a detective who is willing to bend the rules to catch criminals. Song Min-jae as young Ko Moo-chi Suh Dong-hyun (ko) as teen Ko Moo-chi

Han Sang-hoon

Jo Nam-doo / Park Moo

Ma Kang-rim, Woo-chi's nemesis. He grew up with both Mu-yeon and Woo-chi in Yuldo. Kang-rim loved Mu-yeon, but always ended up second best in everything, including winning her heart. He chooses to betray them, setting the story in motion.

Go Jae-hyo, reporter

Gong Chil-goo

Detective (cameo, ep 4)