Angmawa Donggeo Sijak

Kwon Jeong-Ha, a blunt and inflexible college student, hates his handsome and popular classmate Kwak Hyun-Woo, who fooled around with and dumped his senior, whom he secretly had a crush on. The two are like dogs and cats, growling at each other whenever they meet. However, one day, their relationship is completely turned upside down by a suspicious necklace that Jeong-Ha finds.

"It might sound ridiculous, but... I am a 'devil.'"

Hyun-Woo, who reveals himself to be a devil, tells Jeong-Ha that all the magic he had stored in the necklace has been absorbed by him and that if he doesn't get it back, Jeong-Ha will die. The only way to get her magic back is through physical contact! Jeong-Ha ends up cohabitating with the devil.

(Source: Lezhin, translated)