Zoro, the swordsman of the Straw Hat Pirates in One Piece, is a pivotal character in the series and the first member recruited by Luffy on his path to becoming the King of the Pirates. With a fierce ambition to surpass Dracule Mihawk, Zoro aims to become the World's Greatest swordsman, both for Luffy and his childhood friend Kuina. Through the years, Zoro has made significant progress and acquired numerous power-ups to defeat his adversaries. However, some of his power-ups have proven to be more formidable than others.
9 Sandai Kitetsu
Zoro's search for new weapons led him to pick up the Sandai Kitetsu during the Loguetown arc. This cursed sword proved to be a challenge for Zoro, as he had to overcome its curse to wield it. However, once he succeeded, the Sandai Kitetsu provided him with a significant power boost due to its graded nature. This sword has become a valuable asset to Zoro in his battles.
8 Yubashiri
Just like the Sandai Kitetsu, Yubashiri also offered Zoro a significant power boost. He received Yubashiri as a gift from the sword seller who he bought Sandai Kitetsu from.
The Yubashiri was known to be one of the 50 Wazamono Grade Swords. This sword was known to be light and easy to handle, yet had a sharp edge nonetheless. Unfortunately, Yubashiri ended up dying at the hands of Shu, a member of the Navy.
7 Breath Of All Things
Zoro's battle against Mr. 1 proved to be a pivotal moment in his combat evolution. He acquired a unique skill known as the Breath of All Things, which allowed him to harness his inner spirit and discern what to cut and what not to cut. As his adversary was constructed from steel, Zoro had to master the art of cutting steel, and that's where the Breath of All Things came in handy. Essentially, the Breath of All Things is comparable to Ryuo, a type of Haki that was prominent in the Wano arc. By accessing a rudimentary form of Ryuo, Zoro was able to inflict damage on Mr. 1 during their encounter.
6 Shusui
Zoro's skills were put to the test in the Thriller Bark Arc when he faced off against his own ancestor, Ryuma. Ryuma wielded the powerful black blade, Shusui, which was one of the 21 O Wazamono swords. With this sword, Zoro's attack power was greatly enhanced, as evidenced by the massive slashes he was able to produce, particularly in his fight against Oars.
5 Asura
The origins of Asura, one of Roronoa Zoro's most powerful abilities, remain shrouded in mystery. With this ability, Zoro can manifest two heads, four arms, and four legs, allowing him to unleash devastating attacks with his Nine Sword Style.
Essentially, Asura triples Zorro's attack power and makes him stronger than usual. He used this skill against Kaku in the Enies Lobby arc and also against Kaido in Wano.
4 Observation Haki
During the two-year timeskip, Zoro underwent intense training under Dracule Mihawk to hone his sword skills and understand the true meaning behind swordplay. Additionally, he dedicated a considerable amount of time to mastering Haki, specifically the art of Observation Haki.
Although not on par with Sanji or Luffy in terms of proficiency, Zoro has become a proficient user of Observation Haki. This skill has proven to be invaluable in battles throughout the New World, allowing him to detect opponents and maintain an unwavering level of alertness.
3 Armament Haki
Under the guidance of Dracule Mihawk, Zorro mastered the art of Armament Haki. By enveloping himself in an armor-like coating, Zorro increased both his defense and offense capabilities.
Zorro's Armament Haki is incredibly potent, as demonstrated in his battles against formidable opponents like Pica and King. His proficiency in the Color of Arms Haki suggests that he has significant potential for further growth in this area.
2 Enma
Zoro received a powerful sword that once belong to Kozuki Oden, named Enma, in the Wano arc. This blade belongs to the 21 O Wazamono swords and is believed to be exceptionally difficult to master.
Enma requires a worthy wielder who is skilled enough to control its power. The sword drains the Ryuo of its wielder, making it a challenging weapon to handle. However, those who can fully master Enma are deemed capable and worthy of wielding the legendary blade of Kozuki Oden. After Zoro wielded Enma, his swordsmanship skills improved significantly, and he claimed to be stronger than ever before.
1 Conqueror's Haki
The rare and powerful ability known as the Color of the Supreme King, or Conqueror's Haki, is possessed by only a select few in the world of One Piece. Among these individuals, Zoro stands out as a wielder of this incredible skill, as evidenced by his use of it during the Wano arc.
In a remarkable display of strength, Zoro was able to imbue his swords with Conqueror's Haki while battling Kaido, ultimately leaving a lasting scar on the fearsome creature. As he continued to hone his mastery of this ability, Zoro later employed it to devastating effect in his fight against King, ultimately emerging victorious over his powerful foe.