Enma is the strongest blade that Zoro owns at the moment. It's one of the 21 Great Grade swords, with the potential to become as strong as one of the twelve Legendary Grade swords. Zoro accepts the challenge and takes Enma, hoping to turn it into a black blade.
Enma. Enma is also one of the 21 Great Grade swords (and one of the strongest) presently in Zoro's possession in One Piece. Prior to him, it was possessed by the legendary Kozuki Oden, who even used the Enma to slay Kaido. It is the only sword along with Ame no Habakiri, which has managed to leave a scar on Kaido.
Either a) by the same logic Shusui is technically a grade weaker than Enma, Zoro would still have a weaker blade in Enma than Mihawk's Yoru and WB's Murakumogiri, both blackened Saijo O Wazamono swords, which should be stronger than blackening an O Wazamono sword like Enma.
The Wado Ichimonji is a sword of great personal importance to Roronoa Zoro. It was forged by Shimotsuki Kozaburo and was once a prized heirloom of his family. It is also one of the 21 Great Grade swords. After the death of its previous owner, Kuina, Zoro asked for it from her father, who then gave the sword to him.
What is Zoro's weakest sword? Out of the swords he currently owns, the Sandai Kitetsu is the weakest blade in his arsenal.
Thus, Zoro's power grows threefold, as he can use his nine swords to slice an opponent thrice more than usually, and Zoro tends to do so by rushing past his foe at high speeds. Zoro developed Nine Sword Style before the two-year timeskip, first showing use of it during his intense duel with the CP9 agent Kaku.
Later, in the fight against King, Zoro used Conqueror's Haki to tame Enma completely. Eventually, Zoro managed to coat all his swords in what appears to be the advanced form of Conqueror's Haki, making him one of the strongest swordsmen in the story now.
As one of the 50 Skillful Grade Swords, Yubashiri was a rare and reliable weapon that served Zoro's unique fighting style well. It was destroyed during Zoro's fight with Shu on Enies Lobby, and was later left alongside the Rumbar Pirates' gravesite on Thriller Bark.
Dressrosa Arc
After he saw it, Kin'emon became determined to challenge Zoro so the sword could be returned to Wano Country. While at a restaurant in Acacia, Shusui was stolen by a dwarf named Wicca. Zoro caught the dwarf and reclaimed his sword.
Nidai Kitetsu is a moderately curved katana with a light purple edge and a distinct blue hamon that has the appearance of flames.
Luffy's "Nidai Kitetsu" Katana (Luffy Sword)
Wado Ichimonji is Zoro's most treasured weapon as it was been given to him by his master after his childhood friend and greatest rival's untimely death. It's become both a piece of prized equipment and a reminder of their promise to become the strongest swordsman.
Wado Ichimonji is the first named sword that Roronoa Zoro carried in One Piece. It was forged by Shimotsuki Kozaburou, a person from Wano Country. This sword once belonged to Koushiro, the dojo master of Zoro from Shimotsuki village, and was meant to be inherited by Kuina, his daughter.
Dracule Mihawk is Zoro's biggest rival, being the man who holds the title of the World's Strongest Swordsman. Mihawk is extremely skilled with the blade and his swordplay is described as very aesthetic.
Actually not just 1, he can eat 3 devil fruits.
Although, Zoro is famous for wielding three swords, becoming known as the "Three Sword Style", he is proficient enough to wield either two swords and even one, the former being his original style.
The highest grade swords are called Saijō Ō Wazamono. The swords belonging to this category are the rarest. It is followed by Ō Wazamono, Ryō Wazamono, and Wazamono.
In the two-year time skip, Zoro trained under Dracule Mihawk, popularly known as Hawk Eyes Mihawk. One of the popular theories is that the scar on Zoro's left eye is a training mishap. Many believe that Zoro lost his left eye during his training in some sort of accident or battle.
Just as Luffy powered up by creating Gear Second and Gear Third to take down Lucci, and Sanji tapped into the hellish flames of Diable Jambe, Zoro tapped into the power of the demon spirit Asura.
During Sanji's cooking battle in a Loguetown Arc filler episode, it was mentioned that some fish species that should not exist in the East Blue were found due to ocean currents, which made Sanji certain that the All Blue exists.
Zoro x Hiyori
They shared intimate moments and Zoro might even find a sense of belongingness when he's with her. Throughout his tedious journey, Zoro met a lot of potential partners but the connection he seems to have with Hiyori seems special as Wanokuni has immense influence over Zoro's life.
In zoro vs luffy, luffy has greater will, greater haki and pretty much everything. Zoro loses easily.
Monkey D. Luffy has mastered all three types of haki, including Kenbunshoku Haki (Observation Haki), Busoshoku Haki (Armament Haki), and Haoshoku Haki (Conqueror's Haki). He can even use several subforms of the hakis, which makes him one of the most powerful haki users in the One Piece world.
Zoro is the second-strongest member of the crew and that will most likely always be the case in the story. After defeating Kaido's strongest underling, King, Zoro was recognized as the strongest commander of the crew.