That was just me defending that Zoro would not be the one to take down Kaido, as that accomplishment is solely reserved for the character whose goal it is to take down the Four Emperors and become Pirate King. Me talking about Zoro slaying Orochi, was just entertaining the idea that Zoro would replicate Ryuma's legacy of slaying a Dragon. As far as Zoro main fight of the arc is concerned though, I always thought it would be King.