Demon of Envy

Long ago, there was a beautiful woman who was named Sooyeon in the kingdom of Goryeo, she was enlisted to be the next woman that the king will marry but she refused as she already have someone with her. A handsome yet poor peasant who always kept her protected and will love her forever but it didn't take long when the king found out the truth and she starts to flee from the palace with him. However, the guards caught her lover and was sentenced to death. She swore revenge on him and calls a demon to make her invulnerable to the humans, the demon told her she will have to take someone's life so that the deed has been done.

Sooyeon cannot take one's life and that is the problem, so the demon does the deed and it is not the king's life that he took but her younger sister. She starts to transform into something that humans cannot kill, the demon turned her into one of them with the price of her younger sister's soul.  As she walks through the earth she could see people having a brilliant life, she got jealous and starts to devour them. She sinned as she starts devouring humans flesh and when she starts to get conscious by what she had done, she grieved and felt the loneliness over her. She then locks herself in the coffin as she sleep for over the centuries, gaining the title of the Demon of Envy.

Years had passed and Sooyeon woke up as someone took the seal of her coffin away, she got very hungry and devoured a human who opened the coffin. Then she saw that she was drifted to another unknown island, she then starts to live inside the Knightmare Island for 40 years up until now. She became a lazy and skeptic demon, only wanting to sleep all day but she envies people when she got interested into one.