In 2008, novice mangaka Kohei Horikoshi submitted a oneshot to the magazine Akamaru Jump, detailing a world suspiciously like the ones in Superhero comics. Powered folks are publicly recognized as "Heroes", fighting against twisted monsters known as Aberrants and keeping the city streets safe.
Enter one Jack Midoriya, one of the few non-powered people living in this world. Wiry, anemic, but full of determination, Jack makes a living as a sales associate for Akahashi Hero Support, a company that offers gadgets for heroes to use. Despite nearly everything about him making people put his dream to be a hero down, he secretly tries to moonlight as a vigilante, using the tools from his job as his own. One late night mishap earns him the ire of resident hotshot Snipe, mocking Jack for playing hero and dissing his inspiration Positive. Jack declares him an enemy and makes it his mission to prove him wrong.
When another Aberrant starts rampaging through town, Jack (under the guise of a sales run) decides to beat Snipe to the monster and take it out on his own but it injures him brutally and leaves, prompting Snipe to try finishing it off. Jacks director finds out about his secret and the pair have a heart-to-heart, but its cut short when the monster gets out of control and Snipe himself gets incapacitated in the process. Faced with a dire situation, its up to Jack to get back into the fray and learn a whole new way to become a hero...
The oneshot was reprinted in the fifth and final volume of Oumagadoki Doubutsuen, where Horikoshi remarked that he'd like to write it all over again because of how much it meant to him... and boy, did he ever.
Tropes present in the oneshot:
- Always Chaotic Evil: The Aberrants, from what few we see, don't do much but be public nuisances and attack the city.
- Chekhov's Gun: The Beigoma Knuckles that Director Akahashi souped up end up proving to be just the item Snipe needed to finish off the Aberrant.
- Costume Copycat: Jack's hero suit is a tribute to Positive.
- Determinator: Jack, be it through selling weapons or trying to fight crime. It's implied the reason AHS has been getting sales at all is because he keeps pushing himself to sell wares.
- Double-Meaning Title: "My Hero" refers to both Jack being inspired by Positive and Snipe growing to see Jack as his own inspiration.
- Everyone is a Super: Most people in this world have some sort of power. Folks like Jack and Director Akahashi don't, but still manage to get by assisting them.
- Fanboy: Jack and Director Akahashi are huge fans of Positive.
- Loophole Abuse: Due to Jack's frailness, there was no way he'd be able to pass a Hero Exam and get an official license. Workers in hero support get a license by default in order to make and deal gadgets, so he geared himself towards that path to get closer to the action.
- Incompetence, Inc.: Akahashi Hero Support. Its current director has no management experience and keeps overspending on the budget, they're in the red by negative 80 percent, and by the time we first see them they've made exactly two sales. They hadn't always been that way, though: Positive used to love their business. Completely subverted in the epilogue, where business is booming again.
- Make My Monster Grow: After the Aberrant nearly knocks out Jack, it grows several stories high and decides to devour everything in its path.
- Pretender Diss: Snipe lays into Jack when he sees the latter's Positive costume, dismissing him and his inspiration as frauds. Having your past trauma stare you in the face is going to do that.
- Sentai: The vegetable-themed Healthies evoke this trope, complete with "Super Sentai" Stance.
- Surprisingly Realistic Outcome: Jack's first real battle ends in him getting curbstomped. His heart was in the right place, but his body was still too weak to put up a fight.
- Vigilante Man: Jack tries to be one, but his frail body and anemia keep getting in the way.