"Hero of His Own Opinion" follows the journey of Jun-Hyeok, a man who has lived through multiple reincarnations, including a life as a Demon King and a life as a regular human. When he is suddenly summoned back to his original world to serve as its "Hero," he finds the role ill-fitting. Refusing to follow the script of a selfless savior or a mustache-twirling villain, Jun-Hyeok decides to navigate this new life based entirely on his own internal compass. The story subverts the "Summoned Hero" trope by focusing on a character who is unapologetically cynical, pragmatic, and fiercely independent of the world's expectations.