5. JOZU
When Zoro was finally able to cut Daz Bones (Mr. 1), he asked to Zoro: “What’s next? Cutting diamonds?”
Now that line holds a lot of foreshadowing as we have learned in the Marineford War Arc that a certain Commander of the Whitebeard Pirates holds the ability to turn into diamond… And we all know Oda doesn’t just throw things out there for nothing.
There will be a point in the series where Zoro will have to go head to head against Diamond Jozu?
Personally I can’t believe that any of the Straw Hats will fight someone of the remnant Whitebeard Pirates. Does this mean Jozu will die at some point and Zoro will fight the next owner of his fruit?
4. FUJITORA
Zoro should prove his worth against swordsmen who are Devil Fruit users as well. This is where Fujitora comes in. Zoro defeating Fujitora in a duel would be a remarkable feat to add to his resume.
Of course, there is also the theory that Shiliew will absorb Diamond Jozu’s devil fruit power, kill Mihawk and be Zoro’s opponent…so there’s that.
3. SHILIEW OF THE RAIN
Some popular theories claim that Shiliew will get Jozu’s Paramecia-type Devil Fruit and will defeat/kill Mihawk with diamond ability giving Zoro motivations of both vengeance and pride to go after Shiliew. Zoro will “cut diamond” at Raftel, defeating Shiliew.
2. THE OLDEST LOOKING GOROSEI
He is bald, much like Mahatma Gandhi. He is the only one of the five to not wear a black suit or tie. He also holds a samurai sword with him. According to some popular theories, that Gorosei possesses a Kitetsu.
At the moment we know nothing about their powers and backstories but I do believe that all of them have fighting powers:
-They all have battle scars.
-He has one of the greatest swords, if he doesn’t know how to fight why would he go through all the trouble of getting it.
-In the One Piece world, power rules. To become Fleet Admiral you have to be Admiral first, and to do that you need to have Haki and etc.. you get the idea.
My point is that Gorosei has great fighting power, probably even greater than an Admiral.
1. DRACULE MIHAWK
There is only one swordsman who Zoro aims to defeat in order to become the world’s best swordsman and that is none other than Dracule Mihawk, the current holder of the title, “Greatest Swordsman in the World”. Part of Mihawk’s reputation as the most powerful master swordsman in the world is also due to his tremendous superhuman physical power and fortitude which supplements his mastery of swordsmanship. An throughout all of One Piece series Mihawk didn’t get hurt even once!
In the past he was a rival to Shanks, when Shanks still got both arms. Having lost one rival in Shanks, he now shares a rivalry with Zoro, and is prepared to wait as long as it takes for Zoro to become strong enough to beat him.