Jang Seon-yul

as Jin I-soo (child) (8 episodes), as Jin I-soo (teen) (2 episodes)

as Kang Hyeon-u (12 episodes)

as Choi Ha Jun (2 episodes)

as Ok Chan Kyu (young) (1 episode)

as Seo Yul (child) (1 episode)

as Gong Soo Kwang (young) (1 episode)

as Gong Ki-joon (child) (4 episodes)

as Seo Ha Neul (2 episodes)