Dual (2013)

Jacob, a soft-hearted meticulous introvert is the polar opposite of Andre, a sociopath hyper sexual serial killer. Jacob struggles to maintain his girlfriend's interest within their slowly declining relationship as Andre decides to set his own sights on her. Jacob must quickly work up the resolve to fight if he wants to keep Amber from becoming the latest victim of Andre's sadistic habits but only if he can finally come to terms with the terrible link that he and Andre share.