I literally have no idea what’s happening here but from what I can gather
@Paperchampion23 , Stephen Paul’s/Viz translation is correct. It depends on how you structure the sentence.
カイドウに「唯一傷」をつけた伝統の刀
The legendary blade that gave Kaido his only scar.
カイドウに唯一「傷をつけた伝統の」刀
The legendary blade, the only one to have ever scarred Kaido.
If Stephen Paul/Viz went with the latter then I suppose that’s that, although I do see where you’re coming from. Personally I’d also go with the latter to place the emphasis on the blade, not the scar given that it makes more sense in context.