Han Daesung, Back From Hell

Synopsis

On his way home from middle school, Han Daesung is abruptly cast into hell, where survival depends on battling monsters and mastering a game-like system of skills, equipment, and quests. After enduring decades in that hostile realm, he returns to Earth to find that only ten years have passed and his body is recovering in a Seoul hospital. There, hell's system continues to summon him for new missions.