This is, to some extent, related to Zoro. He thinks that Zoro will always use Wado Ichimonji, the finest sword in One Piece, a neutral blade, and a cursed sword.
For now lets talk about the neutral blade and also cursed blade. We will talk about Wano in the end.
First we have the Sandai Kitetsu. It is a cursed blade, has a wicked curve and is described as a sharp sword. It is willing and able to cut indiscriminately. Oda may have based Kitetsu on Muramasa. And let’s just accept that this blade is designed to cut anything and everything.
Kitetsu has been called a problem child on many occasion s by Zoro, being innately bloodthirsty.
However, writer thinks that during first part of the story, Zoro has overcome this issue slowly. Until the Water 7 arc, Zoro doesn’t use lethal force. He restrained and also controlled this blade. Cloudastic thinks that Zoro has mastered this particular blade and the key is to conquer its bloodlust.