Geunyeoui Hero

Kang Tae-gwu is a monster from the future, with the mission to eliminate Jung Eun-ji, the woman who grows up to be the famous Monster Slayer. In order to get close to her, Tae-gwu has disguised himself as a hero named Sunbae. Will Tae-gwu be able to kill the Monster Slayer of the past and change the future?

(Source: Lezhin, translated)