This also is what does not ensure me that Ryuma is Zoro and Zoro is really Ryuma, because how the fuck did Ryuma not recognize that he was literally fighting himself in Thriller Bark? Unless Oda pulls the biggest retcon in manga history, Zoro and Ryuma being the same person ala Luffy and Joyboy is not gonna happen.
At least we never directly knew that Joyboy and Luffy are the same person before this chapter, whereas Monster and Thriller Bark did show that Zoro and Ryuma are two different people. Heck, one uses 1 sword and the other uses 3, whereas Luffy has literally the same power as Joyboy since he is, well, actually Joyboy himself.
@Cinera