On Ju-wan

as Gyeong-hwan (adult)

as Jin-su

as Han Min-oh (14 episodes)

as Kim Jun-young

as Baek Joon-ki (15 episodes)

as Self (2 episodes)

as Self (1 episode)

as Kim Jun-young

as Jin Young-Min (16 episodes)

as Jung Tae-yang (50 episodes)

as Self (1 episode)

as Seok Jun-su (20 episodes)

as Teacher Park

as Dong-gun

as Self (1 episode)

as Seo Ki-hyun (16 episodes)

as Lee Ho-sung (19 episodes)

as Lee Hyun-myung (10 episodes)

as Noh Jung Do

as Kyung Woo-jin