Zoro got the scar on his left eye sometime in the time skip and hasn't opened it since. Although it is a big deal, the reason behind this is still shrouded in mystery. As fans were not provided with answers, they came up with their own theories.
A very popular idea suggests that opening this eye would lead to Zoro unleashing the full power of the demon that is within him. Zoro has often been compared to demons by many characters in the story, such as Kaku, during their fight in Enies Lobby.
As Shanks has given his arm to Luffy for the new generation, Mihawk has given his eye to Zoro. Because he has the sharingan. Kidding, After the two-year timeskip, Zoro gains a new scar running down his left eye, which is now implied to be critically injured as it is always closed.
While nothing official relating to the eye has been learned yet, fans theorized he shut this eye to stop that power (something disproven in the Wano arc). While this is simply one of many theories, the important takeaway is that nothing official has come out regarding Zoro's eye yet.
Enma is the strongest sword possessed by Zoro of the Straw Hat Pirates right now. What is Zoro's weakest sword? Sandai Kitetsu has to be the weakest sword Zoro has used until now in the One Piece manga and anime.
9 Won't Eat: Roronoa Zoro
Wielding three swords, Zoro possesses immense proficiency in this art and, over the course of time, his Haki has been consistently improving as well. For someone like Zoro, eating a Devil Fruit doesn't make much sense because he doesn't need to depend on one.
Regardless of how much stronger he was compared to the vast majority of the people he knew, deep down, he was aware of just far the gap was between him and his ultimate goal. This humbling affected Zoro on a deep level, so much so that it seems to have caused him to become much more serious.
Zoro wanted to see if he was worthy of Mihawks little knife necklace thing so he threw it it the air (like his cursed sword) and it slashed his eye which meant he still wasn't worthy to wield that knife.
It limits his sight and his depth perception in particular, and it would get hair in his open eye whenever the wind blows. You could say its because he's ashamed of his relation to Germa, but if he really cared that much, he would have just shaved the twirly bits off both his eyebrows, like he recommended Duval do.
Zoro was the first person who accepted Luffy's invitation and joined the latter on his journey to become the Pirate King. Zoro is a very powerful fighter and he possesses all three types of Haki. Zoro was able to use Conqueror's Haki unknowingly against Kaido.
The reason is because Zoro understands exactly what Luffy means just by a look or by even Luffy calling his name. Luffy goes to Zoro the most out of anyone on the ship even for the smallest of things. He has proven to understand Luffy the first time when they met each other.
Mihawk outclassed Zoro when the two fought over Baratie, and even now, he is superior to the straw hat swordsman in terms of skill. On the Sabaody archipelago, Rayleigh fought Kizaru and hit him in battle and even wounded him during the battle.
Luffy is trying to convince Red-Haired Shanks to accept him as a crew mate, with the then two-armed captain merely laughing at this child's dreams of piracy. To prove his commitment and toughness, Luffy takes a knife and stabs himself right under the eye, leaving Shanks' crew horrified.
It's entirely possible Mihawk noticed through their duel and training that Zoro suffers from ocular dominance in his left eye. That is to say, the left eye is stronger than the right. As a result, maybe Mihawk scarred the left eye shut and instructed Zoro not to open it until his right eye was trained enough.
He is proficient in both Armament and Observation Haki, as well as one of the few known characters who possess Conquerors Haki.
Zoro usually carries three swords with him to perform the three-sword style anytime. So currently, he has the Wado Ichimonji, Kitetsu III, and Enma with him. What is Zoro's weakest sword? Out of the swords he currently owns, the Sandai Kitetsu is the weakest blade in his arsenal.
He and Jimbei are currently the only known Seven Warlords who do not have Devil Fruit powers. The only duel between Shanks and Mihawk that was actually seen is in the game One Piece: Unlimited Cruise 2.
After the two-year timeskip, Sanji now covers his right eye, shows his left eye, and has grown his hair just slightly longer.
At some point under unknown circumstances, Killer eats a SMILE devil fruit which caused him to lose the ability to express anger and sorrow. He takes on the alias Kamazo the Manslayer.
Zoro tries to fight for Luffy since he lies helplessly on the ground. Through Zoro's efforts, Kuma offers a deal to him. He tells him that he can take all of Luffy's pain away, but has to implant it in Zoro. Zoro agrees to this deal when Kuma says he could die from all of this pain.
He does not smile for quite some time following his victory, because he continues to go through troubling situations. Four episodes pass until he finally smiles again, once he makes a "safe" landing on a building with Nami after using his Devil Fruit powers to trapeze through the air.
In the 98th volume of One Piece, Oda answered a fan question about what Devil Fruits would fit Nami, Zoro, Sanji, Usopp, and Franky best. Nami's Fruit is the Rumble Rumble Fruit, which lets its user wield the power of lightning.
However, he is also an equally important fighter in the crew, being part of the Monster Trio, along with Zoro and Luffy, and, one of the Pirate King's Wings. While Sanji does not have a Devil Fruit, if you were to ever eat one, there are certain ones that would fit him perfectly.
The Sakana Sakana no Mi, Model: Shark(速いチーター Fish-Fish Fruit, Model: Shark) is a Zoan type Devil Fruit that grants the user the power to transform fully or partially into a Shark. The fruit was eaten by Zoy.