Among the straw hat pirates, besides Luffy, the strongest member is Roronoa Zoro. Zoro has proved his strength time and time again and he is on his way to becoming the strongest swordsman ever. During his first fight with Mihawk, Zoro promised his captain that he would never be defeated ever again until he achieved his and Luffy’s dream.
However, he could not fully keep up his promise. Although he almost won every battle since then, he also lost a few. Some characters were able to defeat the “King of Hell”. They were total powerhouses and are considered some of the strongest characters in the entire One Piece series.
1. Bartholomew Kuma
Bartholomew Kuma was an officer and founding member of the Revolutionary Army, as well as a former Warlord of the Sea and king of the Sorbet Kingdom. It was during the Thriller Bark Arc that the Straw Hat Pirates met him. Kuma had been given the order to eliminate every member of the Straw Hats.
Being one of the two Straw Hats who was still conscious, Zoro attempted to sever Kuma’s head but was unsuccessful and knew instantly that he would be defeated by Kuma. Zoro had to give Kuma his own life to save Luffy admitting his defeat against the character.
The previous tyrannical leader of Skypiea was Enel. After being a resident of Birka, Enel used Goro Goro no Mi’s power to destroy his home country before leading his followers to conquer Skypiea. Every opponent Enel faced, including every Straw Hat member, was easily defeated, giving the impression that he was unbeatable. Enel was probably one of the strongest opponents the Straw Hats ever faced.
Zoro chose to challenge him, but the god of Skypiea slandered him in the end. Enel defeated Zoro with ease in an instant, and it was arguably the hardest defeat for Zoro since Mihawk.
Kizaru serves as a Marine admiral. Of the three Navy Admirals that were there before, Kizaru is the only one still standing. With only his physical strength, Kizaru was able to match an older Rayleigh blow for blow. Throughout the Sabaody Archipelago arc, Kizaru proved to be the most formidable foe, vanquishing nearly every pirate in the area, including the Worst generation.
Kizaru was accompanied by Sentomarou and the Pacifista, which made the situation worse. Zoro was helpless and would have perished if Kuma and Rayleigh hadn’t intervened to save him.
Renowned as the “Strongest Creature” in the world, Kaido is the Governor-General of the Beasts Pirates and was once one of the Four Emperors who governed the New World. In a single night, Kaido faced off against Yamato, the members of the worst generation, and the nine red scabbards, nearly annihilating all of them.
It became pretty clear during Zoro’s battle with Kaido that Zoro would never be able to overcome someone as skilled as Kaido. Zoro barely hurt Kaido when he used his strongest attack to leave a small scar on him. Using a Raimei Hakkei, he defeated Zoro to show off his strength.