Kang Sung-jin as Cha Bong-sub (ep 3–6) Serial killer who murdered three women, including Young-gyu's mother and Dong-ho's friend Mimi.
Kang Sung-jin sebagai Cha Bong-sub (ep 3-6) Pembunuh serial yang membunuh tiga wanita, termasuk ibu Young-gyu dan teman Dong-ho Mimi.