Triangle: Cast
HERO Jaejoong
Heo Young-dal / Jang Dong-chul
Yim Si-wan
Yoon Yang-ha / Jang Dong-woo
Lee Beom-soo
Jang Dong-soo
Oh Yeon-soo
Hwang Shin-hye
Baek Jin-hee
Oh Jung-hee
Park Ji-yeon
Sung Yoo-jin
Kim Byeong-ok
Ko Bok-tae
Kim Hye-eun
Kim Ok-kyung
Mun Jung Hyun
Min Su
Hong Seok-cheon
Man-kang
Kim Ji-young
Oh Jung-hee's grandmother
Park Hyo-ju
Kang Jin
Jung Ji-yoon
Kang Hyun-mi
Noh Young-hak
Jang Dong-soo (young)
Kim So-hyun
Hwang Shin-hye (young)
Kim Byeong-gi
Yoon Tae-jun
Oh Soon-tae
Wan Bae