Are you sure that it is the Armament Haki? Maybe it could be Conqueror Haki...
Take a look to this theory and come back to vote and discuss!
I think it's a different perspective to what the fandom is currently believing.
Actually the key point is that Armament Haki is common, but Black Blades aren't. And why is Zoro still confused about black blades if it only involves Armament Haki that he knows very well?
The answer could be that to make black blades he needs CoC in order to exert his will at fully extent over the blades
Take a look to this theory and come back to vote and discuss!
I think it's a different perspective to what the fandom is currently believing.
Actually the key point is that Armament Haki is common, but Black Blades aren't. And why is Zoro still confused about black blades if it only involves Armament Haki that he knows very well?
The answer could be that to make black blades he needs CoC in order to exert his will at fully extent over the blades