A Werewolf Boy

Song Joong-ki

As Wolf-Boy / Chul-soo

Park Bo-young

As Young Sun-yi / Eun-ju

Yoo Yeon-seok

As Ji-tae

Lee Young-ran

As Sun-yi

Jang Young-nam

As Sun-yi's Mother

Kim Hyang-gi

As Sun-ja

Yoo Seung-mok

As Professor Kang Tae-shik

Shin Bi

As Dong-mi

Woo Jung-kook

As Mr. Jung

Goo Bon-im

As Mrs. Jung

Lee Jun-hyeok

As Policeman

Soel Oh-shin

As Thug 1 (uncredited)

Han Min-hik

As Thug 2 (uncredited)

Chuay Kwong-lak

As Thug 3 (uncredited)

Sung Du-hyung

As Man in Black Suit 1 (uncredited)

Cha Jong-ho

As Man in Black Suit 2 (uncredited)

Seo Dong-soo

As Army Colonel (uncredited)

Jung In-gum

As (uncredited)

Lee In-ho

As (uncredited)

O Yeong-seok

As Policeman 2 (uncredited)

Ku Lu-han

As (uncredited)

Kim Chul-jun

As Construction Worker at Market 1 (uncredited)

Park Young-shik

As Construction Worker at Market 2 (uncredited)

Kim Seung-hun

As Public Official (uncredited)

Koo Kyo-hwan

As Drunk Man (uncredited)

Kim Eun-sook

As Military Chief (uncredited)

Hong Sung-ki

As Acupuncturist (uncredited)

Hung Hi-kwon

As Hospital Doctor (uncredited)

Lee Min-woong

As Dr. Kang's Assistant (uncredited)

Nam Jung-hee

As Dong-suk's Grandmother (uncredited)

Ahn Do-gyu

As Dong-suk (uncredited)

Kim Hae-eun

As Woman Renting Mr. Jung's Room (uncredited)

Lee Sung-ju

As Sun-yi's Son (uncredited)

Jang seo-yi

As Sun-yi's Daughter-in-Law (uncredited)

Jo Jae-yun

As Sun-yi's Grandson (uncredited)

Kim Jong-goo

As Sun-yi's Father (uncredited)

Shin Yeong-cheol

As Eun-ju's Boyfriend (uncredited)

Seol Woo-sin

As Gangster 1