"Are you really going to try to become a 'King'?"
This is the start of it for Zoro imo, Oda's going to develop and explore Zoro's strength, and character, as a Conqueror/Leader/King.
To be the lead, to become a king, Zoro is now incorporating his Emperor's Will onto Enma. With the goal of a World's Greatest Title and his promise to Luffy on his back.
It's funny, people say Zoro shouldn't be the one to kill Kaido, that is Luffy opponent, Zoro is just a subordinate. But in this arc Oda is playing with the very concept of Zoro "the Conqueror/Leader", becoming a king.
Great spoilers no wonder it was trending on twitter.