[ Oh. He does settle down a little when Shoto starts carding his fingers through Izuku's hair, (rabbit) ears twitching before he relaxes into it, trying to think what to say. He can't explain exactly how he came into his quirk, because that's a secret (which Kacchan figured out) and Izuku would rather do a great many things than break All Might's trust.

But. This much information is public record, and someday it'll eventually come out, even though he's never exactly brought it up with his high school class. ]

My Quirk came really, really late. [ As in never. Until a miracle occurred. ] So up through middle school, everyone thought I was Quirkless.

[ He's not sure if Shoto has ever actually encountered how people sometimes act around those without a Quirk. But kids can be cruel, and he's maybe smart enough to get what Izuku's trying to say. ]

I don't really blame anyone for what happened, or anything. Kids can be pretty cruel, and our society is pretty Quirk-based.