In the world of One Piece, Zhang Bairen, wielding a demon sword, headed to the backyard of the dojo.

Koushirou, who was meditating and practicing sword Zen, suddenly opened his eyes and looked at Zhang Bairen who was walking towards him.

A glint of light flashed in his eyes for a moment, then disappeared.

“Master, the demon sword has drunk blood,” Zhang Bairen said bluntly.

"How are you feeling?" Koushirou asked with a smile.

"I didn't feel anything," Zhang Bairen answered honestly.

"Bai Ren, I will not ask about your secret."

However, you should not go astray.

"Can you guarantee me that?" Koushirou continued to ask.

“Of course, I can assure you,” Zhang Bairen nodded in reply.

“Alright, in that case, we can begin the second phase of learning.” Koushirou said, picking up the famous sword beside him.

Zhang Bairen was somewhat curious. Was the second stage about learning new sword techniques?

"I have told you before about the different levels of swordsmanship and the different levels of swordsmen."

"Next, I will teach you the power of dominance!" After saying this, Koushirou slowly drew his long sword.

An unbelievable sense of surprise welled up in Zhang Bairen's heart.

At first glance, one could see a pure black line covering the entire blade.

This is—Armament Haki!

In Wano Country, it is also known as Ryuo.

"See that? This is Armament Haki, one of the three types of Haki that can be mastered through training," Koushirou explained.

"I've already told you about the basics of Haki, so I won't go into detail about the specific effects of Armament Haki."

"Look, this is just an ordinary famous sword. But once you apply Armament Haki to it, it becomes even stronger and sharper without any effort," Koushirou said, pointing the sword at the ground.

With a gentle stroke, a noticeable scratch appeared instantly on the grassy ground.

With a gentle thrust, the entire blade sank directly into the ground.

This is not only Armament Haki, but also a higher-level Ryuo, making it the best Armament Haki in terms of defense penetration!

After sheathing his sword, Koushirou continued, "Now, I'll close my eyes. You can attack me at will. If you manage to touch me, I can grant you any request that isn't unreasonable."

Zhang Bairen was somewhat excited, but he understood perfectly.

This is clearly a demonstration of Observation Haki. With his own strength, if Koushirou were to dodge seriously, he would not be able to touch the opponent even a little bit!

Unless, the hidden Naruto ninjutsu is exposed!

"Is it worth it? Is it worth exposing myself?" Zhang Bairen hesitated, feeling somewhat nervous.

"Guina is eleven years old this year, right..." Thinking of this, Zhang Bairen's expression instantly became extremely firm.

"Master, don't underestimate me!" Zhang Bairen said, then drew his sword and charged into battle.

Koushirou closed his eyes, made no attempt to defend himself, and quietly awaited Zhang Bairen's attack.

Whoosh!

A flash of sword light appeared, and Koushirou stepped to the side, dodging Zhang Bairen's sudden attack.

Then, Zhang Bairen continued to swing his sword, slashing away large amounts of mud and grass.

"Interesting. Are you guessing that I rely on hearing and perception to make distinctions and predictions?" Koushirou asked.

Zhang Bairen remained silent, continuing his frenzied attacks, simultaneously using his fists and feet to knock away dirt and grass as he attacked Koushirou.

Koushirou continued to dodge, and not a single speck of mud and grass flying around him landed on him.

Swish, swish, swish! !

The sheathed longsword was swung continuously, and the raging wind from the blade scattered all the surrounding debris.

Seeing that the situation was not good, Zhang Bairen suddenly roared loudly and used the Buddhist Lion's Roar technique.

In addition, he threw the demon sword and its scabbard, one into the air and the other towards Koushirou.

In the instant the sound reverberated, Zhang Bairen swiftly completed several hand seals.

This is the Substitution Technique, and in terms of life-saving ability, it is comparable to an S-rank god-level ninjutsu.

Because, to some extent, the Substitution Technique has special properties similar to space-time ninjutsu.

Sensing Zhang Bairen's strange behavior, Koushirou immediately made a reasonable response.

First, dodge the demon sword and its sheath, then dodge the falling dirt and grass, and then guard against Zhang Bairen who makes strange hand seals.

However, Koushirou did not expect this.

As he stepped on the inconspicuous bits of grass, an unexpected pair of hands grabbed Koushirou's thigh.

Bang!

As white smoke appeared, Zhang Bairen, who had turned into shredded grass, grabbed Koushirou.

The Substitute Technique and the Transformation Technique are simple applications of the Three-Body Technique.

Koushirou was quite surprised. Was this Wano Country's ninjutsu?! It didn't look like it at all.

When did his disciple, who grew up in Shimotsuki Village, learn ninjutsu?

Could this be some kind of Devil Fruit ability?

At this moment, Koushirou was filled with doubt.

"Haha, I've run into you, Master!" Zhang Bairen shouted excitedly.

Koushirou opened his eyes and looked at the jubilant Zhang Bairen.

"Hyakunin, what kind of ability is this? Don't tell me you created this yourself!" Koushirou asked.

Zhang Bairen picked up the demon sword and its scabbard, then looked at Koushirou and answered very seriously, "This is ninjutsu, true ninjutsu."

As for its origin, it was passed down to me by my brother not long ago.

"Ninjutsu!? Brothers!?"

"Hyakunin, where is your brother? May I see him?" Koushirou asked.

“Not for now, he’s not in this world.” Having been prepared, Zhang Bairen chose to lay his cards on the table decisively.

After twelve years of getting along, Hokage Zhang Bairen's ability to sense good and evil allowed him to be certain that Koushirou was not a bad person and had no ill intentions towards him.

"Not in this world? It was an accident..."

"I'm so sorry, Hyakunin. It was my oversight; I didn't consider this situation." Koushirou bowed deeply in apology.

“Master, you’ve misunderstood. When I said ‘not in this world,’ I meant literally, not in this world!” Zhang Bairen’s explanation left Koushirou somewhat bewildered.

"I have some questions now, could you explain them to me?" Koushirou asked.

Zhang Bairen nodded, then replied in a deep voice, "Of course."

However, things may be a bit complicated, or even a bit unbelievable, so I hope you are prepared.

It's best not to let anyone else know the content of our conversation.

Koushirou sat on the ground, his face grave, and replied, "Alright, I can confirm that no one on this island can hear our conversation!"

Zhang Bairen had no doubts, because some people's Observation Haki was indeed extremely outrageous.

“Master, you must have noticed something strange when you adopted me.”

As a child, I suddenly appeared in Shimotsuki Village without any news of my parents or any trace of them, as if I had appeared out of thin air.

"Aren't you curious about this situation?" Zhang Bairen asked.

After careful consideration, Koushirou suddenly realized that he seemed to have deliberately overlooked this aspect of the problem.

Thinking of this, Koushirou's expression became even more serious.

PS: In the One Piece lore, Haki was originally said to be colorless, but now it's clear that it does have color. Armament Haki is basically black.