LUFFY VS KOBY: It’s a fated battle between two friends. The future Pirate King against the future Fleet Admiral.
ZORO VS FUJITORA: This fight was anticipated in Dressrosa, where Zoro and Issho clashed. Zoro needs to 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.
SANJI VS KIZARU: Sanji vs. Kizaru is a pretty expected fight by fans. Both use kick attacks, Sanji exclusively uses them while Kizaru’s strongest attacks are kick attacks. Sanji specializes in Observation Haki, Kizaru is the fastest, to the point where you cannot even react to him. This fight will probably happen near the end of the series, if so, Sanji’s Observation Haki will probably be at it’s peak, probably fast enough to react to Kizaru by then.
MONKEY D. LUFFY VS AKAINU: Luffy’s revenge for Ace’s death. Maybe he will take his revenge with the help of his brother Sabo.
SABO VS AKAINU: Ace fought Akainu for Whitebeard’s honor and eventually sacrificed his life for his little brother- Luffy. Sabo could fight Akainu in order to save Luffy, however, this time he wouldn’t die.
LUFFY AND TRAFALGAR LAW VS KAIDO: Trafalgar D. Water Law and Monkey D. Luffy, teamed up with the sole purpose of overthrowing Kaido of the Yonko, the strongest creature in the world! It’s possible that also Eustass Kid will join them in order to take revenge on Kaido.
SHANKS VS BLACKBEARD: This fight has been hinted a lot. Those Shanks’ scars, Shanks’ concern about Blackbeard’s rising strength, Blackbeard outright saying at the end of the war it’s not the time for their fight implying there will be one.
MONKEY D. DRAGON VS BLACKBEARD: Blackbeard is currently targeting the Revolutionaries, but can he really defeat the most dangerous and most wanted man in the world?
ZORO VS MIHAWK: This fight has been hyped up since the beginning of the series. Mihawk is the current holder of the title, “Greatest Swordsman in the World”. Because of his status, defeating him is Roronoa Zoro’s ultimate goal.
MONKEY D. LUFFY VS BLACKBEARD: The ultimate fight for the title of “Pirate King”. Blackbeard is the greatest rival of Luffy. He’ll certainly be his final obstacle at Raftel.