If you are looking for a text based on the general sentiment of being a hero, the topic usually centers on finding strength in everyday actions: I Am a Hero | Animanga Wiki

However, Hanazawa uses the title ironically. For much of the series, Hideo survives not through bravery, but through paranoia and luck. He is often selfish, cowardly, and mentally fragile. Yet, it is precisely these flaws that make his journey resonate. When he finally takes actions that are genuinely heroic—protecting others at great risk to himself—the impact is seismic. He isn't a hero because of a birthright or a prophecy; he becomes one through the agonizing choice to do the right thing when he is terrified.

What makes the manga I Am a Hero so compelling is the tension between Hideo’s self-perception and reality. Hideo clings to the idea that he is the protagonist of a story. He constantly mutters reassurances to himself, attempting to mold his life into the structure of a shonen manga. He wants to be the hero who saves the girl and defeats the monster.

Kengo Hanazawa is a stickler for detail. Hideo does not dual-wield infinite ammunition. He carries a single, bolt-action rifle (and later a pump-action shotgun). The manga spends entire chapters on the logistics of reloading under stress, the weight of ammunition, the recoil, and the psychological weight of pulling the trigger.