During this arc, Zoro and Luffy, having lost their memories, confront each other and engage in a fight. It is during this fight that Zoro lands a strong surprise attack on Luffy, slicing his chest and thus giving him the X-shaped scar.
The arc is actually a loose adaption of a 2003 PlayStation game titled One Piece: Ocean's Dream! During this arc, Luffy and a hypnotized Zoro end up fighting, resulting in an X scar across Luffy's chest when he was wounded by Zoro.
SMH. Luffy got his scar on his chest from Roronoa Zoro this happened while Zoro's being controlled on Episode 223 from 10:55 - 11:10.
In fact, I'm going to tell you exactly which episode of One Piece features Luffy getting his scar so you can NOT watch it. It happens in Marineford in episode 487 right after … Ace dies.
Zoro got his scars in the Baratie arc ( Sanji's arc ). His goal is to become the strongest swordsman in the world. For that to happen he has to defeat the current world's strongest swordsman Dracule Mihawk. While Luffy was facing an enemy in the Baratie arc ( Don Krieg ) Zoro encounters Mihawk.
Now, in his profession and to fulfill his dream, perfect eyesight plays a major role. So this theory suggests that Mihawk noticed this and scarred Zoro's left eye, which is supposedly suffering from ocular dominance, and instructed Zoro to keep it shut until he trains his right eye to become strong enough.
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.
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.
Everyone knows that Luffy's straw hat was given to him by Red-Haired Shanks, his hero, and role model. However, what might not be known by everyone is that it was originally owned by the legendary Gol D. Roger. Roger wore the hat until he eventually handed it off to Shanks, who handed it to Luffy when he was a child.
First off the scar is on his left eye. Zoro gained the scar after undergoing two years of training with Mihawk. It was at some point in between that 2 timeskip that Zoro obtained the scar over his left eye.
Shanks got his scar from Blackbeard the time he was with the Roger Pirates or before he created his own crew. At the meeting (ep. 434) with Whitebeard, Shanks said they have been fighting since then, means that Shanks got his scar before he became the captain of Red Hair Pirates.
That said, there is one crew member who stands above the rest in terms of loyalty to Luffy: Roronoa Zoro.
Luffy is the protagonist of the anime/manga series One Piece and the love interest of the pirate Empress Boa Hancock.
Many fans have speculated that it's due to a combination of his Armament Haki and rubber, with the former creating so much resistance as Luffy's arm stretches that it literally causes his fist and arm to ignite.
Crocodile was the president of the secret criminal organization, Baroque Works. He is the longest running primary villain of One Piece as well as the first villain to defeat Luffy. He ate the logia-type devil fruit, the Suna Suna no Mi (Sand Sand fruit).
In Chapter One of the Manga he stab himself with a dagger in the eye to prove himself.
It was originally a treasure that Shanks and his crew took from a CP9 member Who's Who, but was accidentally eaten by the series protagonist Monkey D. Luffy. In the second version of Romance Dawn, it originally belonged to Luffy's grandpa who took it from an unspecified enemy.
Over the years, he has come a long way and become one of the strongest pirates on the seas. Zoro has attained terrific strength, but he does not rely on a Devil Fruit at all.
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.
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.
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.
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.