Special S00 E01

Ji Chang-wook (as Baek Dong-soo) Yoo Seung-ho (as Yeo Woon) Park Gun-tae (as Yeo Woon (young)) Yeo Jin-goo (as Baek Dong-soo (young)) Yoon Soy (as Hwang Jin-joo) Lee Hye-in (as Hwang Jin-joo (young)) Shin Hyun-been (as Yoo Ji-sun) Nam Ji-hyun (as Yoo Ji-sun (young)) Hong Jong-hyun (as King Jeongjo) Choi Min-soo (as Chun) Jun Kwang-ryul (as Kim Gwang-taek) Park Jun-gyu (as Heuk Sa-mo) Park Won-sang (as Jang Dae-pyo) Oh Man-seok (as Crown Prince Sado) Park Cheol-min (as In) Jeon Kuk-hwan (as King Yeongjo) Lee Won-jong (as Hong Dae-ju) Jung Ho-bin (as Im Soo-woong) Ahn Suk-hwan (as Seo Yoo Dae) Lee Yong Woo (as Kenzo) Kim Hee-jung (as Lady Park) Yoon Ji-min (as Ji)

martial arts rivalry romance historical friends to enemies based on manhwa