Lee Woo-jin

Lee Woo-Jin is the main antagonist in the film Oldboy. He seeks out revenge on Oh Dae-su, a man who briefly attended the same high school as him.

High School
On the day before Dae-su was to transfer to a different high school in Seoul, he saw Woo-jin sleep with his own sister, Soo-ah. They both saw him watching and Soo-ah recognized him. Dae-su, who didn't realize that they were brother and sister, told his friend, Jyoo-hwan, about it, starting a rumor that Soo-ah was a slut. Dae-su then moved away and forgot what he saw, as it wasn't very important to him. However, the rumor grew to say that Soo-ah was pregnant, and she began to believe it. She displayed psychsomatic symptoms that made her appear pregnant. Believing that everyone would find out about her and Woo-jin if the child was born, she resolved to kill herself.On July 5th, her and Woo-jin visited a local dam, and she tried to jump off. Woo-jin caught hold of her hand as she was hanging, and tried to stop her. She convinced him to let her fall. When the autopsy determined that she was not pregnant, Woo-jin was consumed with guilt and sought revenge on Dae-su.

Dae-su's Imprisonment
Years later, Dae-su became a drunken reprobate, who got drunk and missed his daughter's birthday. Woo-jin had him kidnapped off the streets, and imprisoned in a hotel style room for fifteen years. During this time, Woo-jin had a pacemaker placed in his chest, and had the doctor make a remote which could automatically turn the pacemaker off, killing him. Just before he had had Dae-su released, Woo-jin hired a hypnotist to make him meet and fall in love with a female sushi chef named Mi-do, who had been similarly hypnotized. He released Dae-su, who now could only think of revenge. Dae-su and Mi-do met and fell in love, according to plan. Woo-jin left enough clues for Dae-su to find him, and when he did, he told Dae-su to find out who he was by July 5th, or he would kill Mi-do. Dae-su began to investigate with the help of Jyoo-hwan, who now owned a cyber cafe. Dae-su went to visit his old school, and when he did so, he remembered what he saw, except now he understood. In the meantime, he and Mi-do made love, after which Woo-jin gassed the room and visited them to make sure his plans were working out.

Confrontation
Dae-su followed the clues, and visited Woo-jin's penthouse. There he explained that he knew what he had done and understood why he had been imprisoned. Wo0-jin then siad that Dae-su had been asking the wrong question: "Why was I imprisoned?" He should have been asking, "Why was I released?" As an answer to that question, Woo-jin showed him a photo album. The first photo was that of Dae-su with his wife (now deceased) and daughter. Each photo showed girl get a little bit older, the final showing Mi-do. Woo-jin had made Dae-su sleep with his own daughter. Dae-su then went hysterical, begging Woo-jin no to tell Mi-do. He even sliced out his own tongue as symbol of his silence. Seeing the state he had driven Dae-su into, Woo-jin agreed not to tell Mi-do. He went to the elevator, leaving Dae-su in the penthouse with these parting words:"My sister and I loved each other in spite of it all. Can you two do the same?" Woo-jin, thinking back on his sister's death, shot himself in the head before the elevator reached its destination.