Zoro at end of one piece wins, he will beat Mihawk (If everything works out) if its just pure swordsman skill. Shanks will win with Haki, but I'm not including that. Ryuma we don't know anything of him to much. We can guess he was INSANELY strong but I still guess Zoro will become the strongest swordsman in all history. Zoro wins 👑👑👑👑