Your Closet Monster

While everyone else was reincarnating as beautiful women and adorable animals, she somehow ended up as a gloomy monster living in the male lead's wardrobe. Worse, she was supposed to be the very monster that tormented him. According to the original story, he should've been terrified of her. But instead, he told her that her horns were beautiful, gave her a name, and even asked her to stay with him at night. To him, she was no longer just a monster. She was his monster.

(Source: Webtoon Entertainment)