Just me thinking

One for all was given originally to All For One younger brother, who was quirkless and didn't like the way his older brother was using quirks to cause madness. All for one forced his quirk onto his brother and the brother passed it down (or something like that) so his brother could be defeated(?)


I honestly don't think his quirk was meant to be "passed down" I think his brother meant for him to only use it, because the younger brother was weak. Something must of happen for it to be able to be passed down by the dna or whatever. (eat this!) I think, me assuming, this whole thing is assuming by the way, that the younger brother alternated it in his own way on accident? The older brother might of tried to take it back, but it wouldn't work (he might not of had the power to take quirks yet. Maybe he did. Maybe it didn't work on him if he attempted it) and tried to kill his brother or lock him up? He could of at least done that. And since it wasn't a quirk that was meant to be "given" it becomes a bit corrupted with each generation that uses it and Midoriya didn't have his generation right xD