Demon Slayer Virgil [Isekai One Piece]

As Zavia walked through the research facility, he carefully observed the layout of the surroundings, committing every detail to memory.

After thirty minutes of heading towards their destination, Zavia and Arthur arrived at a large iron door.

He cautiously scanned the area, ensuring there were no immediate threats, and then deactivated his Spatial Distortion. They had encountered numerous surveillance Den Den Mushis on their way here.

It was clear that these were in place to prevent intruders and also to keep the children from escaping.

In the original story, there was a room within Punk Hazard known as the Biscuits Room, where children from all over the world were held as test subjects.

Some of these children had been kidnapped, others sold by their own parents, and some came from orphanages...

Their backgrounds were diverse and often tragic.

"What is this place?" Arthur asked, walking around the iron door with a puzzled expression. This room seemed different from the others they had passed.

Zavia examined the door, tapping it lightly with his hand. It was sturdy and cold to the touch, but it was just ordinary iron. The Yamato blade could easily cut through it.

In terms of swordsmanship, Zavia had reached the level of a Sword Master. His ability to unleash sword energy was a clear indicator of this.

Not everyone could generate sword energy; it was a skill that required years of dedicated training and mastery.

Furthermore, Zavia had also achieved the ability to "cut what he wanted to cut and leave what he didn't want to cut," a testament to his precision and control.

He hadn't wasted the past year. Besides strengthening his spatial abilities and physical combat skills, he had focused heavily on swordsmanship, his core fighting style.

In fact, he had dedicated more time to swordsmanship than anything else, spending at least sixteen hours a day honing his skills.

However, whether he had reached the level of a Great Swordsman like Mihawk was uncertain. He hadn't had the opportunity to truly test his swordsmanship against a worthy opponent.

The swordsmen in the first half of the Grand Line were simply not on his level. If he wanted a true challenge, he would have to seek out someone like Rayleigh.

But the old man was rarely home, often venturing out on his own adventures for indeterminate periods, sometimes returning after a few days or weeks, other times after months or even a year. His movements were unpredictable.

Back to the matter at hand, even if Zavia wasn't a Sword Master, he could still easily cut through ordinary iron. The sharpness of the Yamato blade was renowned, capable of slicing through even space itself.

Zavia extended his Observation Haki, sensing through the iron door.

He detected numerous "people" inside, but strangely, they were all motionless.

This puzzled Zavia. What was going on in there?

He glanced to the side and noticed a console-like device next to the door.

Upon closer inspection, he realized it was a mechanism for opening the iron door. In the center of the device was a handprint scanner, requiring a specific hand as a key.

"Arthur, step back."

After a moment of thought, Zavia decided to force the door open, but he didn't want to create too much noise.

The Yamato blade materialized in his hand. He placed his hand on the hilt, and in the next instant, a silver flash of light streaked through the air.

A crack appeared on the iron door, followed by the lower half slowly sliding down.

A wave of cold air rushed out as the door was cut open. Zavia stepped forward, his expression turning into one of shock.

Inside, countless humans were frozen solid, their bodies lining the walls from floor to ceiling, their faces contorted in expressions of agony and terror.

"So this is some sort of freezer, but for humans... and prisoners, at that."

Zavia's gaze swept across the room, noting that all the frozen individuals were wearing prison uniforms.

This gruesome sight didn't faze him in the slightest. He had seen too much bloodshed and horror during his travels in the past year.

Furthermore, during his time as a Rear Admiral, he had killed many people and witnessed his fair share of gore. While this was the first time he had encountered something like this, it wasn't particularly terrifying.

At least not to Zavia...

Thump, thump, thump, thump...

Suddenly, the sound of hurried footsteps approaching from behind reached his ears. Zavia's eyes narrowed, and he instantly activated Spatial Distortion to conceal himself and Arthur.

"Hurry! The intruders are at the freezer!"

A loud shout echoed from the distance. Ten seconds later, a group of guards arrived at the scene.

"Damn it! They got away!" The leader of the group cursed in frustration. "Quick! Find them!" He barked orders at his subordinates, who dispersed immediately.

However, the leader didn't leave. He circled the iron door, examining the cut marks and the control console.

He lowered his head in thought, seemingly trying to deduce the type of enemy they were dealing with. But he quickly gave up and left after one last glance at the scene.

Once the leader was gone, Zavia and Arthur reappeared.

"Strange, how did they discover us so quickly?" Zavia looked in the direction the leader had left, a puzzled expression on his face. Arthur also felt something was amiss.

He had been with Zavia for a long time and was familiar with his concealment methods, though not to the extent of understanding the specifics.

He knew that once Zavia activated his Spatial Distortion, it was nearly impossible for anyone to detect him unless they were significantly stronger.

However, this time, they had only been inside the building for thirty minutes before the guards arrived. While they hadn't been discovered, it was still strange.

What did this mean? It meant that among the enemy's ranks, someone possessed perception-type magic!

Arthur's face paled as this realization dawned on him.

"Hmm? What's wrong, Arthur?" Zavia's Observation Haki detected the fluctuation in Arthur's emotions, and he turned to look at the boy.

"Uh, big brother, I think I know why we were discovered."

"Hmph? Let's hear it." Instead of dismissing Arthur's words like a typical adult might, Zavia was intrigued.

"I suspect that the reason we were discovered so quickly is because someone in this building possesses perception-type magic."

"Perception-type magic?"

"Yes. As the name suggests, it allows the user to sense everything around them. It's commonly used by spies and intelligence agents.

However, perception-type magic isn't always about actively releasing magical power and receiving blurry images. Some types require external tools to function, and the clarity of the images can vary. Some simply detect the number of enemies, while others allow the user to see and hear everything within their range."

Arthur explained the characteristics and functions of perception-type magic, his knowledge impressive.

Where did he learn all this? Don't forget, Arthur came from a wealthy family who had built two 2-cubic-meter rooms filled with magical books for him to study.

And Arthur himself had a strong interest in magic, so he would memorize any useful information he came across, like the knowledge he had just shared about perception magic.

"Someone specializing in perception magic? No wonder they found us so quickly." Zavia's eyes widened in understanding after hearing Arthur's explanation. So among the outsiders, there was someone who focused on perception magic.

But this raised another question: why hadn't they attacked yet, if they were aware of Zavia's presence?

Did they overestimate their own strength, assuming their subordinates were enough to handle him? Or were they wary of Zavia's power and using the guards as a distraction while they made their escape?

And if they had sensed Zavia, why did the guards seem clueless, as if they had simply been informed of intruders without any specific details?

If the enemy had a perception magic specialist, they should have detected Zavia's unique aura. Yet, they had only sent a group of weak guards to deal with him?

That was ridiculous!

Unless...

Zavia pondered, recalling Arthur's explanation of perception-type magic.

"It seems their perception magic is limited to detecting the number and general location of enemies, not their strength."

He suddenly remembered Arthur's words, "Some simply detect the number of enemies," and everything clicked into place. However, this particular magic seemed to be more advanced, allowing the user to sense the general direction of enemies as well, but not their specific location.

"If that's the case, then let's head straight for them. There's no point in hiding now that we've been discovered. Though I wonder how Mihawk is doing."

Having reached a conclusion, Zavia decided to confront the outsiders directly. His perception was different from theirs. He used Observation Haki, which allowed him to pinpoint the exact location of individuals.

A prime example of this was during the Dressrosa arc, when Usopp, using his Observation Haki, had accurately targeted Sugar from a distance of at least a kilometer with his giant slingshot.

Zavia felt that Observation Haki in the One Piece world was similar to Nen in Hunter x Hunter, though he couldn't quite put his finger on the exact similarities and differences.

Spatial distortions rippled as Zavia activated his ability, concealing himself and Arthur once more, leaving behind only a trail of cold air.

…

"Hey, Spirit, are you sure we don't need to deal with those intruders ourselves?"

Deep within the research facility, a group of individuals dressed in attire foreign to this world stood before a circular platform made of a special alloy.

One of them, a man with golden hair and armor, spoke with a serious expression, addressing a woman cloaked in a black robe beside him.

"Of course. They're just another group of pirates trying to steal valuables. My perception magic is never wrong. Nobody knows perception magic better than me." The woman in the black robe winked playfully.

"Is... is that so... Alright then."

The man looked at her with a hint of exasperation, seemingly annoyed by her behavior. He then turned his attention back to the platform before them.