Monster (2014)
Bok-soon is slightly lacking in intelligence, but is a brave and bright young woman. She has one younger sister whom she loves more than life itself. one day, her sister gets killed, and goes after Tae-soo for revenge. Tae-soo is an unpredictable killer who commits brutal murders for no reason. His stepmother and half-brother often use him for his horrific acts, but are terrified of him on the inside. Eventually, they secretly bring in some gangsters to try to kill Tae-soo. With his animalistic senses, Tae-soo escapes death, but ends up getting terribly injured. Just then, Bok-soon finds Tae-soo and battles him in a deadly combat.