Your parents were colleagues with some Japanese heros, including All Might before his retirement. Then one day, they left for work but didn’t come back. His soft heart couldn’t help but take you in as his own. Even if your parents were gone, you figured you could at least honor them by being a hero too. So All Might took you in, trying to be a good parent.
Though of course, one day he’d explain the power of his quirk, and he even offered if you’d want One for All. But you turned it down, not wanting too have too much power. Besides, it didn’t feel like it was for you. And you were right. All Might found his successor, Izuku Midoriya. When you both got into UA, you made sure the secret of his quirk was kept that way. But, there was one problem
Izuku’s childhood acquaintance, or friend in his own words, Katsuki Bakugo was skeptical on how Deku suddenly had an overpowered quirk when he knew he grew up quirkless. You weren’t fond of bullies, so you resented Katsuki for a long while.
But then things started changing. First it happened when the USJ training center was attacked by the League of villains. And then months later the class kept encountering them. Then it happened at the training camp, you got found out and kidnapped, All For One having figured out your connection with All Might. Not only that, but Katsuki got taken as well. You weren’t sure what to do. Things would’ve been fine if it was just you, but a classmate too? It didn’t help that he was being reckless and threatening the league. The situation wasn’t getting any better. Until finally, it did. Right after Katsuki attacked first after they took off his chains, thinking he’d agree to join them, the building shook but not from explosions.
The heros were here, and the moment All Might barged in you knew things would be okay. What you didn’t know was that it was his last fight. All for One appeared that night, All Might’s archenemy that sought out only power. He felt helpless as you had watched them fight after being rescued away from the villains, Katsuki having to carry you himself while propelling into the air with explosions as their friends called to them.
The last, weakening embers in All Might were leaving him since he passed One for All to Izuku. But he still had that fight, but still, the fear was there when you thought you’d lose someone else again. You didn’t notice it but Katsuki squeezed your hand, trying to reassure both himself and you while also piecing the pieces together.
After that day, All Might was officially retired, now frail but still passionate to keep the next generation of heros prepared. You knew more was to come, both with the League of Villains interest in both you, Izuku, and Katsuki.