As the loyal right-hand man of Monkey D. Luffy, the master swordsman Roronoa Zoro is a major fan-favorite in One Piece. Episode 1060 of the anime, titled The Secret of Enma! The Cursed Sword Entrusted to Zoro, featured the green-haired pirate as its absolute protagonist.
Engaged in a fierce fight with the mighty King, Zoro tapped into his memories until he finally unleashed all his power, revealing himself as one of the few characters in the series who are able to use the Color of Conqueror's.
Zoro's kingly ambitions as a powerful Conqueror's Haki user are revealed in One Piece episode 1060
Conqueror's Haki: the act of imposing one's willpower
As the deciding factor for most battles in One Piece, Haki is the strongest power in the series. While most fighters can use Observation and Armament Haki (although few reach a notable level of mastery), the very rare Color of Conqueror's is only available to those born with it.
Conqueror's Haki users can impose their own will on others, overwhelming their targets. It can't be learned but is only used by the few chosen ones - one in several million people - who are born with the rare traits of a "Supreme King".
Conqueror's Haki users have the greatest ambitions. They possess superior willpower and potential, which allows them to overwhelm their opponents. The weakest people can't even face them, getting intimidated or even losing consciousness when in their presence.
The power of one's Color of Conqueror directly grows stronger as the user becomes stronger overall. Even among the "Supreme Kings," only a few are strong enough to coat their bodies, weapons and attacks with Conqueror's Haki, achieving a whole new level of might.
The skill is yet to receive an official name, but most One Piece fans conventionally call it the "Advanced Conqueror's Haki." Characters who can use this power are inherently among the strongest by the mere virtue of possessing such an ability.
Since its introduction in the series, this power has been notably emphasized as a game-changing resource. The mighty Kaido described it as the signature ability of the mightiest fighters, separating the best from the mere good.
Remembering the past, Zoro gains awareness of his future
Involved in a heated battle with King, Kaido's right-hand man, Zoro was in trouble. Factoring in his Lunarian powers, King endured all of Zoro's attacks, despite them packing enough power to hurt even Kaido, as shown in the previous fight between Supernovas and Emperors.
Moreover, one of Zoro's three swords, Enma, started reacting uncontrollably, triggering his Haki and causing him to leave himself open to King's attacks. While the fight raged, Zoro remembered his encounter with a Wano samurai named Kozaburo Shimotsuki.
This fateful meeting from Zoro's childhood owned the key for him to master Enma fully and ascend to new heights. According to Kozaburo, each sword has its own personality, and to properly wield the blade, the owner must first figure out the sword's will and adapt to it.
Kozaburo was a prominent swordsmith, and Enma was his best creation. However, this sword had the habit of testing the wielder by draining away his Haki. If lacking power, the user will have all his Haki fatally stolen.
Realizing that Enma had been testing him, Zoro met the blade's expectations, becoming a worthy wielder like Oden Kozuki. To fully please the sword, Zoro decided to go all out with his Haki.
Surrounded by a bunch of henchmen, Zoro unleashed his Conqueror's Haki, causing them to pass out instantly. Witnessing the scene, King asked Zoro about his "kingly ambitions," to which he answered that he must fulfill them to honor his promises to his captain and best friend.
What does it mean for Zoro to be a Supreme King?
The idea that a superior Haki equates to a stronger character isn't true for every single comparison. However, for the majority part, it is. In One Piece, the most resolute fighters have greater willpower, which results in a more powerful Haki, allowing them to potentially overcome any obstacle.
Those who own all three types of Haki are especially respected in the One Piece world. They are the people who lead, not the ones who tag along. Zoro refused the Baroque Works' offer to join the organization, saying that he would only join if he was made the boss of the group.
Nevertheless, Zoro decided to follow Luffy. However, he didn't join him as a mere subordinate but as a partner who believed in him out of spontaneous trust. Zoro even threatened to kill Luffy if he ever hindered his dream to become the World's Strongest Swordsman.
Over time, Zoro and Luffy have become a formidable duo. As his right-hand man and the only crewmember who is, to a certain extent, comparable in power to him, Zoro has often acted as Luffy's vice-captain, protecting him when in danger and replacing him if needed.
As the future World's Strongest Swordsman and a natural-born Supreme King who can even use Advanced Conqueror's Haki, Zoro's ambition and potential are comparable to Luffy's, paralleling the connection between "Dark King" Rayleigh and the Pirate King Gol D. Roger.
Zoro's powerful figure has often led bystanders to wonder why he doesn't lead the Straw Hats or his own crew. However, Zoro decided to follow Luffy and honors this promise by not stepping out of his position unless strictly necessary.
His dream to become the World's Strongest Swordsman comes from his "kingly ambitions." The World's Strongest Swordsman is indeed the king of all swordsmen, i.e., the one who surpasses them all, sitting at the top of the world as the most powerful. Being a Conqueror's Haki user who can even use the advanced version of this power, Zoro can perform something that most users of this ability aren't strong enough to do.
Final thoughts
From Monet being paralyzed in fear to Queen getting intimidated by Zoro's ambition, One Piece author Eiichiro Oda has left a lot of cues to foreshadow the "Pirate Hunter" being a Conqueror's Haki user. The most obvious hint was Kaido perceiving Conqueror's Haki from Zoro's Ashura attack, which involves the green-haired swordsman exerting his willpower to create the illusion of his body multiplicating like a demon.
During the fight with King, Zoro gained awareness of the enormous power that laid dormant within him and fully unleashed it. A testament to Zoro's strength, he was immediately able to use the Advanced Conqueror's Haki, ensuring himself a place in the elite of the strongest One Piece characters.