 Song Joong-kiWolf-Boy / Chul-soo | Wolf-Boy / Chul-soo |
 Park Bo-youngYoung Sun-yi / Eun-ju | Young Sun-yi / Eun-ju |
 Yoo Yeon-seokJi-tae | Ji-tae |
 Lee Young-ranSun-yi | Sun-yi |
 Jang Young-namSun-yi's Mother | Sun-yi's Mother |
 Kim Hyang-giSun-ja | Sun-ja |
 Yoo Seung-mokProfessor Kang Tae-shik | Professor Kang Tae-shik |
 Shin BiDong-mi | Dong-mi |
 Woo Jung-kookMr. Jung | Mr. Jung |
| GGoo Bon-imMrs. Jung | Mrs. Jung |
 Lee Jun-hyeokPoliceman | Policeman |
| SSoel Oh-shinThug 1 (uncredited) | Thug 1 (uncredited) |
| HHan Min-hikThug 2 (uncredited) | Thug 2 (uncredited) |
| CChuay Kwong-lakThug 3 (uncredited) | Thug 3 (uncredited) |
| SSung Du-hyungMan in Black Suit 1 (uncredited) | Man in Black Suit 1 (uncredited) |
| CCha Jong-hoMan in Black Suit 2 (uncredited) | Man in Black Suit 2 (uncredited) |
 Seo Dong-sooArmy Colonel (uncredited) | Army Colonel (uncredited) |
| JJung In-gum(uncredited) | (uncredited) |
| LLee In-ho(uncredited) | (uncredited) |
| OO Yeong-seokPoliceman 2 (uncredited) | Policeman 2 (uncredited) |
| KKu Lu-han(uncredited) | (uncredited) |
| KKim Chul-junConstruction Worker at Market 1 (uncredited) | Construction Worker at Market 1 (uncredited) |
| PPark Young-shikConstruction Worker at Market 2 (uncredited) | Construction Worker at Market 2 (uncredited) |
| KKim Seung-hunPublic Official (uncredited) | Public Official (uncredited) |
 Koo Kyo-hwanDrunk Man (uncredited) | Drunk Man (uncredited) |
 Kim Eun-sookMilitary Chief (uncredited) | Military Chief (uncredited) |
| HHong Sung-kiAcupuncturist (uncredited) | Acupuncturist (uncredited) |
 Hong Hee-wonHospital Doctor | Hospital Doctor |
 Lee Min-woongDr. Kang's Assistant (uncredited) | Dr. Kang's Assistant (uncredited) |
 Nam Jung-heeDong-suk's Grandmother (uncredited) | Dong-suk's Grandmother (uncredited) |
