You died young, due to a quirk accident. Your body was given a quirk not suited to it... and you exploded. Just like your Uncle Yoichi had. You never did meet your uncle, as he died before you were created. According to your dad, it was all Kudo's fault, the 2nd user of one for all. Your dad had always been fixated on the users of one for all, the current user at your time being Hikage Shinomori. The only reason you'd gotten the quirk from your dad was because he was getting irritated by how well Shinomori had been evading him, and needed extra help.
Which led to your death at the ripe age of 16.
Since then, you'd spend your time in a white void, doing nothing other than going insane, thinking about how you could've helped your dad win if only you were stronger.
Then one day, a hole opened up in the void. Through it, you could see a space like void, filled with rubble. Curiosity won you over, and you ended up leaving into the space void through the hole. You moved through the void, eventually spotting a weird looking platform. There were 8 chairs on it. And 7 people. You recognised 3 of them. Yoichi, Kudo and Lee. Another one matched the description of Shinomori your father had given you.
You decided to keep your distance and observe for a while. And after however long of observing, you came to a conclusion; these were all the past users of one for all. Which meant it must've been ages since you died.
On one occasion, you noticed a teenage boy in the void, covered in greenish black mist. He clearly didn't belong in the void, and after more observation, you realised that this was the current user. The eight? or maybe the ninth, considering the extra chair.
The boy seemed to come for a short time, and leave for prolonged periods of time. During this time, you found out his name was Izuku Midoriya, and that he was your own age. Were the heroes getting that desperate that they were using kids? This fact made you happier; it must've meant that your dad was winning.
However, you began to get restless. This boy, your dad's enemy, was at your fingertips, and you weren't doing anything. You didn't do a thing when you were alive, and you weren't doing a thing now that you were dead. You wanted to help, desperately. So, you began to think about what you could do, anything, to aid your dad.
What could you say to a hero that would tear them apart?
When the boy next visited, it clicked. You knew what to do.
Currently, Izuku was speaking to the vestiges about his progress with black whip to the vestiges. He'd mostly gotten the hang of it, and just wanted some advice, which the vestiges could provide.
Whilst they conversed, a hand came from underneath him, grabbing his ankles. Izuku looked down in panic, not knowing what the heck that was. And not a second after, he felt himself getting dragged into somewhere. The vestiges panicked and called out to him, going to grab him, but he disappeared into nothing too quickly.
Izuku found himself in a white void, alone. He'd never seen this place before in his dreams, and the vestiges didn't seem to have seen it either.
Izuku turned around, and somebody came into his vision. They had strikingly white hair, and weirdly emotionless grey eyes. He spoke up, addressing the person..
"Where- where are we..? And who are you..?"