There is no clear "deuteragonist" in One Piece like let's say Naruto, My Hero Academia, Black Clover, etc. OP is more structured like Dragon Ball and Bleach where you have Goku and Ichigo as the MC and the rest of the cast are major supporting characters. Some might say Vegeta is the second MC of DB but there's also Piccolo, Gohan, Trunks, etc. But if I have to pick a character that can fulfill the role of the deuteragonist of OP, it's gotta be Zoro.






