One month later.
On the second floor of the Marine Headquarters fortress, inside a small training room.
Roya stood there, holding his sword in one hand, the blade held horizontally in front of him. He was completely focused, staring at the blade of Engetsu. Around the blade lingered a faint, unusual aura.
This aura was Armament Haki.
"Armament… Hardening!"
With a thought, Roya attempted to compress and condense that strand of energy.
Buzz!!
Under Roya's control, the aura began to compress toward the surface of Engetsu's blade. However, before it could condense to a sufficient degree—before the black coloration could appear—it suddenly collapsed and dispersed.
"Hah… one month really is too short. The Armament Haki I've trained isn't strong enough yet, and my control isn't sufficient either. I still can't achieve Armament Hardening?"
Roya muttered to himself as he watched the scene. After taking a deep breath, he continued training.
In truth—
From the moment he began training Haki, it took less than half a month for Roya to successfully train Armament Haki. At this point, he could already make Armament Haki wrap around his sword.
He just couldn't yet make it adhere to the blade and form Armament Hardening.
While training Armament Haki, he was also training Observation Haki—and in that regard, Roya progressed even faster.
In just a few days, Roya had already mastered Observation Haki.
This also confirmed one of Roya's earlier suspicions.
The foundation of Observation Haki was indeed a state of emptiness and clarity. When this state was directed toward the path of swordsmanship, it became "focus," the Breath of All Things. When directed down another path, it became Observation Haki.
Observation Haki was an ability that allowed one to capture an opponent's movements in advance, enabling dodging or preemptive attacks.
The stronger one's Observation Haki, the finer the details one could perceive, and the wider the range one could sense. Aside from that, there were no real tiers or levels.
If one insisted on naming a higher stage, there was indeed one—
The Voice of All Things.
This was the ultimate realm of Observation Haki. It was said that only the Pirate King, Gol D. Roger, had ever reached this level.
At this stage, one could communicate with all things, whether living or inanimate. For example, the Poneglyphs that recorded the history of the Void Century from eight hundred years ago—Roger did not need to decipher the writing on them; he could directly understand their contents.
Ordinary people found it extremely difficult to reach this level through training alone. Observation Haki at this stage was practically a completely different kind of ability.
Roya's terrifying training speed dealt a heavy blow to Zephyr.
At the beginning, Zephyr could still offer him some guidance. Later on, however, Roya hardly needed any instruction at all.
By now—
Even Zephyr had grown numb to Roya's frightening pace of progress.
At first, when Roya mastered Observation Haki in a matter of days and trained Armament Haki in half a month, Zephyr was so shocked he hardly knew what to say.
Now, even if Roya suddenly told him that he had already mastered Armament Haki and could use Armament Hardening, Zephyr probably wouldn't be shocked anymore—at most, he'd be mildly surprised, then accept it as only natural.
He had prepared himself to teach Roya Haki carefully and thoroughly, step by step. Yet once Roya truly began training Haki, Zephyr discovered that there was almost nothing he could teach him.
In many areas, Roya understood things instantly. In even more cases, Roya could do exceptionally well on his own, without any guidance at all.
Fortunately—
Unlike physical conditioning, Haki training also required extensive practical combat training.
Since Roya hardly needed theoretical instruction, Zephyr devoted himself wholeheartedly to practical training, often personally stepping in.
During this period, Garp passed by and observed Roya's training as well. Aside from his shock, he felt genuine satisfaction at Roya's performance.
That said, seeing how devoted Zephyr was, Garp felt something a little strange—he couldn't tell whether Roya was his nephew, or Zephyr's.
---
Once Observation Haki was awakened, the rest was simply a matter of gradual improvement. Armament Haki, however, was different. Even after training it, Roya was unable to achieve Armament Hardening for quite some time.
It wasn't until the second month of Haki training that Roya finally managed to use Armament Hardening—but not freely or consistently. There was still a chance of failure.
Even so, this training speed was already terrifying.
In just two months, he had grasped how to control Armament Haki and how to make it adhere and condense. If Roya's soul were not far stronger than that of ordinary people—granting him vastly superior control over himself—this would have been completely impossible.
When using Armament Hardening, Roya succeeded only once or twice out of ten attempts.
As training continued, the success rate steadily increased—from one or two successes out of ten, to three or four, then five or six…
Now, more than two months after beginning Haki training, Roya's success rate with Armament Hardening had exceeded eighty percent, gradually approaching full mastery.
Boom!!!
Inside the small training room, Roya threw a punch, smashing straight through a thick steel plate. His fist was coated in pitch-black Armament Haki.
"So this is the difference… simply wrapping Armament Haki versus condensing it into Armament Hardening. The gap is enormous."
Roya looked at the power of his punch and couldn't help but marvel.
He had previously tested the effect of merely wrapping Armament Haki, and the increase wasn't particularly dramatic. But once the Haki condensed and adhered to form Armament Hardening, the resulting boost was on an entirely different level.
With Armament Hardening, the power of Roya's punch was nearly double that of a punch without Haki.
The effect of Armament Haki manifested directly as increased attack power. In essence, it was an enhancement to the most fundamental attack attribute of Roya's soul sword.
Although Armament Haki did not increase strength or speed—only attack and defense—the magnitude of that increase was truly frightening.
"Let's test how much it boosts slashes…"
Roya drew Engetsu, took a deep breath, and focused completely. Armament Haki appeared once more, rapidly wrapping around the blade.
Buzz!!
A strand of energy wrapped around Engetsu's blade, but during the condensation process, it suddenly collapsed—apparently due to insufficient Haki strength.
"Failed again? This doesn't seem like a control issue. It looks like my Armament Haki still isn't strong enough."
Roya studied the blade thoughtfully, then focused again without giving up, releasing Armament Haki once more.
Buzz!!
This time, it didn't fail. Engetsu's crimson blade was swiftly dyed with a layer of jet-black sheen, as if it had become a black blade.
Roya swung his sword.
Slash!!
A nearby thick steel plate was split cleanly in half, the cut surface perfectly smooth, gleaming with a metallic luster.
Next, Roya slashed diagonally toward a distant steel plate. A burst of sword energy erupted, slicing through the air before striking the target.
Clang!!
The sword energy swept across the steel plate, cleanly severing one of its corners.
"The boost to pure slashes is also nearly double. The enhancement to sword energy is slightly weaker—probably because my control over Armament Haki still isn't sufficient."
Watching this, a satisfied smile appeared on Roya's face.
Nearly double the power.
For the Roya of a few months ago, doubling attack power wasn't particularly impressive. But for the current Roya, a twofold increase was unquestionably terrifying.
Roya's growth rate had already slowed significantly compared to before. At a normal pace, it would take several months of training just to increase his physical strength by thirty to fifty percent.
In this world, Haki was a power perfectly suited to almost anyone—a direct enhancement to strength. Devil Fruits, on the other hand, usually increased power indirectly through various abilities, and often required time to fully develop and adapt.
It wasn't that Roya lacked Devil Fruits he desired. Rather, the ones he wanted either had never appeared, or were already claimed. Obtaining a suitable Devil Fruit still depended heavily on luck.
Haki, however, involved no luck at all.
It was pure strength, earned entirely through training.