CoA hurt the real body but won't negate df powers...
haki isn't turned on 24x7 but what difference does blackblade make from the normal blade if you have to apply haki all the time? there was no where mentioned or indicated that blackblade is a pinnacleof CoA...all it implied that blade turned black from countless battles ...simple hardening coating can turn blade black albiet temporarily as shown in manga...if black blade being the pinnacle of CoA, then it means it is permanently coated haki or something else?
it also means Kinemon is skilled enough to cut that level of attack...boro breath is just an elemental attack...
1). Won't neagate but it will hurt the real body yes? That means buggy would have gotten hurt and died, if Mihawk was indeed using CoA haki.
2). Idk about that. We will see later whenever Zoro or someone else turns it into a black blade, or via a Ryuma flashback.
Simply using haki on a blade wouldn't make a black blade though, and it wouldn't be considered special if it was just that easy.
If that were the case, there should be more than just 2 known blades that are black blades in the whloe of op, and the likes of Oden and Shanks have not yet managed to make one.
3). Yes Kinemom is skilled. I'm not taking away anything from him. Just disappointed that Kaido breath isn't beyound that.