Stand User Deku

Prologue

Izuku Midoriya had never had the best life, since his 'quirk' was something only he could see, and he never wanted to hurt anyone. Everyone thought he was quirkless. Eventually, his grandfather explained to him that what Izuku had was a Stand: a projection of one's spirit in the form of a fighting avatar. Izuku soon began training with his Stand with the help of his grandfather: Joseph Jostar. He trained it in secret, since his Stand was one of the most powerful ones in existence: Time Destroyer. He quickly learned about the two forms and what they were capable of, but never used them. Then, one day, a slime villain attempted to attack him. Izuku quickly has Hakumen defend him, slicing the viscous villain away from him for a few minutes before All Might showed up and captured the Villain. Unfortunately, the villain escaped, and took Bakugou hostage in an attempt to escape capture. Izuku arrived at the scene and rushed in to battle, throwing his pencils at the villain's eyes to incapacitate it before pulling Bakugou free. They were about to be captured, until Izuku uttered two words. 

"Help, Susanoo." 

His Stand's more powerful form appeared and blasted the creature into oblivion. None of the reporters knew what had happened, but Izuku was scolded for his recklessness. Katsuki confronted him about it, but Izuku kept his quiet. 

"Even if I told you, you wouldn't believe me. 

Shortly after Bakugou left, with Izuku promising him that he'd explain everything to him one day, All Might showed up and offered his quirk to Izuku. The boy accepted, but he never told All Might about his Stand, since All Might obviously couldn't see it. He continued pretending to be powerless, but trained his body to accept All For One. He also used Hakumen to slow down and rewind time, allowing him to train much more than he would have been able to normally. Izuku was ready to accept All For One a mere 5 months into his training, and got to spend the next five months training with All For One. 

He quickly learned that using all of AFO in a single hit was a bad idea, as his body still wasn't ready to deal with the backlash, so he instead decided to use a small percentage of AFO: about five percent. He also worked on using it throughout his whole body at once. 

Two months into his training, Izuku passed out in the middle of it and was confronted by two of the previous users of OFA: 'First' and the third user: Ragna.