In Mask Girl, Ju Oh-nam is Kim Mo-mi’s colleague and the first person to discover her secret identity. Ahn Jae-hong plays the role of Ju Oh-nam.
Like Mo-mi, Ju Oh-nam was always ridiculed for his looks. As he was short and chubby, he was bullied when he was in school. When he realized that no one will bully him if he stays out of sight, he almost became an invisible man.
He grew up trying to hide himself until he disappeared completely. Eventually, he started fearing being seen by people. He works at the same place as Mo-mi, but it is like he does not exist. No one sees or hears him until he makes his presence known.
Oh-nam is a very lonely man. His mother thinks he is good at everything and never sees him for what he is. He is not able to live up to his mother’s high expectations, and his mother’s tough love is not what he needs, so he distances himself from her as well.
He starts looking for companionship in animate objects. He fills his house with pornographic comics, toys, and life-size dolls; he pretends that the dolls love him. Additionally, he is the number one fan of Mask Girl.
A fan’s fanatic love
Oh-nam loves Mask Girl, so he is able to figure out that his colleague Kim Mo-mi is Mask Girl when he sees the moles on her hand. With time, he starts believing that he is in love with Mask Girl.
He spends a lot of money on Mask Girl’s performances and even gets to chat with her, who comes to know him by his username, Once Upon A Prince. However, it is clear that he does not truly love her. When he sees her taking Mr. Park to a motel, he gets jealous and threatens to expose her secret identity.
Later, a fan of Mask Girl’s, Handsome Monk, gets the chance to meet her in person. Handsome Monk intends to take pictures of Mo-mi and reveal her face to all her fans without her consent.
Oh-nam finds out about this and tries to warn Mo-mi, but Mo-mi does not answer his calls or messages. When Handsome Monk forces himself on Mo-mi and she injures him, she sees Oh-nam’s messages and decides to call him for help.
She tells Oh-nam what happened, and he stops her from reporting the murder. Oh-nam sends Mo-mi home and tries to dismember the body, only to find out that Handsome Monk is alive. This makes him panic, and he ends up stabbing Handsome Monk to death.
He then finds out that Mo-mi has quit her job and is moving somewhere else. Mo-mi wants a fresh start, but Oh-nam thinks that she owes him her love. Mo-mi knows that he is the one who threatened her earlier, so she tells him that he is not any different from men like Handsome Monk.
This leads to Oh-nam raping her. However, when he takes off her mask and finds her face covered in bandages, he gets surprised, and Mo-mi takes the opportunity to stab him. She then dismembers his body, puts it in a suitcase, and throws it away.
When the police find Handsome Monk’s body in Oh-nam’s apartment as well as all the pornographic content, they find out that he has psychological issues. They also think that he fled with Mo-mi, but they are proven wrong when his body is found.
Mo-mi, who only tried to defend herself, becomes the lead suspect in the murder case. Oh-nam’s mother, Kim Kyung-ja, never even considers the possibility of her son being in the wrong and takes it upon herself to kill Mo-mi to get revenge for her son’s death.
Also Read: Kim Kyung-ja: Mask Girl character explained