Jang, however, is a monster without remorse. Between their encounters, he continues murdering innocent people, including a teenage girl and a bus full of passengers. He also recruits two cannibalistic accomplices. Eventually, Jang deduces Soo-hyeon’s identity and kills Soo-hyeon’s surviving family members—his father-in-law and younger sister.
Kim Soo-hyeon is a top secret agent in South Korea’s National Intelligence Service. His life shatters when his pregnant fiancée, Joo-yeon, is brutally murdered by a sadistic serial killer named Jang Kyung-chul. Joo-yeon’s body is found dismembered in a ditch. fylm I Saw the Devil 2010 mtrjm awn layn - fasl alany
Soo-hyeon walks away, broken. He has become a devil himself, losing his humanity in the pursuit of vengeance. – If you meant "fasl al-any" (فصل العاني) or a similar Arabic phrase, it might be a mistranslation or an attempt to say "second chapter" or "explicit version." The film has no official Arabic chapter release. If you were looking for a specific scene or alternative cut, please clarify. Jang, however, is a monster without remorse
Driven by vengeance, Soo-hyeon takes a leave from work. Using his elite training, he tracks down Jang. But instead of killing him immediately, Soo-hyeon beats him nearly to death, then inserts a tiny tracking device into Jang’s ear canal. He releases him. Joo-yeon’s body is found dismembered in a ditch
This begins a savage cat-and-mouse game: Soo-hyeon hunts Jang repeatedly, each time inflicting horrific injuries, then lets him go again—hoping to make Jang suffer prolonged fear and pain, not just die quickly.
The climax occurs when Jang kidnaps Soo-hyeon’s sister. Soo-hyeon rescues her, but Jang escapes. In the final confrontation, Soo-hyeon captures Jang and takes him to the place where Joo-yeon was killed. There, Soo-hyeon kills Jang not by direct violence but by setting a trap: he places Jang’s own parents and young son in a room, then forces Jang to watch through a window as Soo-hyeon remotely triggers a device that decapitates Jang’s family. In his final moment, Jang cries out in anguish—the first human emotion he has shown.