Yongsanimi Iljindeureul Mullichyeoyo

The hero who defeated the Demon King and saved the world is summoned to a school full of bullies?! An interdimensional hero is summoned to “Suseong Nam-bu High School,” a hotbed of the worst kind of delinquents. Though the hero never uses his powers against humans, upon facing the “demon-like” reality of these bullies, he decides to teach them a lesson they won’t forget…! Will the hero be able to defeat the bullies and return to his own world? (Source: Naver, translated)