On Ju-wan

as Gyeong-hwan (adult)

as Jin-su

as Han Min-oh

as Kim Jun-young

as Baek Joon-ki

as Self

as Self

as Kim Jun-young

as Jin Young-Min

as Jung Tae-yang

as Self

as Seok Jun-su

as Teacher Park

as Dong-gun

as Self

as Seo Ki-hyun

as Lee Ho-sung

as Lee Hyun-myung

as Noh Jung Do

as Kyung Woo-jin

as Jae-wook

as Self

as Bojang of Goguryeo

as Self

as Jung-hoon

as Yoon-chul / Charlie

as Cha Jin-oh

as Self

as Go Suk-Bin

as Noh Jung-Do

as Il-yeong

as Kim Gangu

as Joong-suk

as Teenager TaeSoo

as Yoo Sung-geun

as Kim Han-soo

as Employee

as Jjaeng

as Han Ji-hoon

as Lee Chang-seob

as Self

as Self