Because Zoro inherited Enma, which contains Oden's will. Inherited will has been a gigantic theme in Wano and we now know that swords possess "wills" or "souls" of their own. Oden's will was to kill Kaido.
Zoro being the "monster samurai" that Kaido said would never come as well as the second coming of Ryuma as has been hinted at both in the manga and in supplementary materials would also be fulfilled
Zoro being the "monster samurai" that Kaido said would never come as well as the second coming of Ryuma as has been hinted at both in the manga and in supplementary materials would also be fulfilled
I read KiriNigiri's post regarding Zkk and it was actually pretty interesting, tho yea she stretched it a bit .
What I'm about to do is I'm already rereading wano.. I'll be making a post regarding my thoughts of the narrative behind this if there is any.