Izuku Midoriya's dormant quirk only activates under specific conditions. His unique quirk manifested just in time to save his childhood bully, and stop the sludge villain's rampage.

Ever need advice from a questionable source? Well then you're in luck Villain Deku is your guy! ( basically just life lessons with poor 'innocent?' Deku) pls read. (art not mine) Once #15 in tododeku

Izuku quit dreaming of becoming a pro hero after three times of being denied. He decided to screw it, and just be normal. He has part time jobs, he recently graduated, he has a car, a nice apartment. And the support from his mom. That is all he needs. What he doesn't need is his childhood bully showing up in his Pro Hero costume outside his door. Or outside the window to his jobs. Or anywhere near him to be honest. But Izuku can't catch a break as Bakugo keeps asking him to become a hero. "Come on. You can become a hero." Bakugo said moving to stand in front of Izuku. "No, bitch. Now move over so I can clean up this spot. Also, fuck you." Izuku retorted with a broom in his hand This is kind of like crack treated seriously. So don't take it too seriously at times.