Article summary:
After the two-year time skip, Roronoa Zoro shocked the world by reappearing with a vertical scar over his left eye, which he keeps permanently closed. Oda still has not provided an official explanation in 2026. Is it merely a training injury or the seal of a demonic power (Asura)? An analysis of the strongest theories.
The Straw Hat crew's second-in-command has sacrificed a great deal to become stronger. By humbling himself before his rival to ask for help, he proved his loyalty to Luffy. But what exactly was the price he paid on Kuraigana Island?
To learn everything about the journey of this legendary swordsman, see his complete profile: Guide to Meito Swords and Zoro's History.
The mystery has remained unsolved since the reunion at Sabaody.
Theory 1: The price of training with Mihawk
The most pragmatic explanation is a battle injury. Zoro spent 2 years fighting the Humandrills (combat-copying baboons) and training with Dracule Mihawk. An accident or a poorly blocked strike can happen quickly against the world's greatest swordsman.
Some believe that Mihawk took his eye to teach him a lesson about observation. Is Mihawk really stronger than Shanks?
Others point to the parallel with Silvers Rayleigh, Roger's second-in-command, who also has an eye scar (but kept his eye open). Zoro follows in the footsteps of legends. To discover the weapons he had to face, read our feature: All About Yoru, Mihawk's Black Blade.
👉 View the One Piece Katana Collection
Theory 2: Controlling the demon (Sandai Kitetsu)
Zoro wields cursed swords, including Sandai Kitetsu. These blades are said to be inhabited by bloodthirsty spirits. The scar could be a seal to contain this thirst for blood.
When he uses the nine-sword technique "Asura," his aura becomes demonic. Keeping his eye closed could help him avoid being overwhelmed by the curse, somewhat like Kenpachi in Bleach. Is the curse of Sandai Kitetsu real?
If he opened this eye, he might unlock a level of power equivalent to Conqueror's Haki. Who are the chosen users of Conqueror's Haki?
👉 Zoro Figurine Collection
Theory 3: The hawk eye and Observation Haki
What if Zoro keeps his eye closed voluntarily? By depriving himself of binocular vision, he forces his brain to develop his Observation Haki (Kenbunshoku) to the extreme.
This is a common technique in manga martial arts. Opening this eye at a critical moment could reveal a pupil resembling Mihawk's ("the hawk eye"), giving him absolute precision to cut through anything, even diamond (his next challenge against Shiryu?). Why Shiryu and the Blackbeard Pirates are terrifying.
To better understand the nuances of Haki, read our guide: Haki Powers Guide.
👉 View the One Piece Earrings
Conclusion: An Eye for a King
Zoro swore never to lose again. This closed eye is the symbol of his vow. Whether it contains a demon or is simply a scar, it makes the character even more "badass."
He now wields capricious blades such as Enma, Oden's former sword. The Secret of the Enma Sword Explained.
Support the future world's greatest swordsman by wearing his colors. The Marimo is waiting for you.