Before the naval soldiers rotated their shifts, Dom and Oboro took the chance to slip into a building and hide inside.
Right after, Oboro summoned the system interface for the very first time. A card appeared out of nowhere in his hand.
He immediately used it on Dom.
The card dissolved into a streak of glowing light and shot straight into the pirate's body.
In an instant, Dom's skin turned bright red. His face twisted in agony, and his limbs jerked and convulsed uncontrollably.
The pain was unbearable. He tried to scream, but Oboro clamped his hand tight around Dom's throat. No matter how hard he tried, not a single sound could escape.
Outside the window, marines patrolled back and forth, yet none paid any attention to the houses lining the street.
It seemed they had just noticed one person was missing from their ranks.
"Uhh… ngh…"
Dom looked as though he would pass out from the sheer torture.
Every organ inside him, down to his very bones, was being forcibly restructured and altered.
Even his skin rippled and writhed continuously, as if something beneath was shifting and rearranging itself.
What Oboro had just used was one of the resources he had obtained from the Demon Slayer world:
A bloodline card belonging to an Upper Rank Demon.
Slowly, minute by minute, Dom's condition finally stabilized.
Yet the result was different from the transformation seen in the Demon Slayer world.
His skin tone had changed slightly, and two small, horn-like bumps had grown out on his forehead.
But overall, he still looked mostly human—the changes were subtle, hardly noticeable at a glance.
"Hmm."
Oboro let go of Dom's throat. He stroked his chin, deep in thought.
He had deliberately used Dom as a test subject.
His goal was simple: to see if powers and abilities from Demon Slayer could be applied in the world of One Piece.
These were two completely different worlds, after all, each with its own unique set of rules and power systems.
Just like his own soul-based abilities— as a high-level power source, he could use them freely in Demon Slayer, mainly because the concept of "souls" was a fundamental part of that world's logic.
But the moment he entered the One Piece world, those abilities met resistance. It wasn't just the will of the world interfering.
There was a basic rule: to use power from outside, the world itself must already have a framework or concept that allows that kind of power to exist.
Higher-level worlds have far stricter limits and laws, something lower-level worlds simply don't have.
Here, any foreign ability or power must adapt and integrate into the existing system—a process of assimilation.
"Is it just… that his physical abilities have improved?" Oboro frowned, dissatisfied.
Without waiting for Dom to regain his senses, he grabbed the pirate by the arm and dragged him over to the window, right where bright sunlight poured in.
The rays fell directly onto Dom, who looked weak and lifeless. But unlike in Demon Slayer, where sunlight burns demons to ash instantly, his flesh didn't scorch, melt, or even smoke.
"Interesting… because of the differences in background and rules, all foreign powers are naturally suppressed by this world. They still work, just not as strongly… It's exactly what happened to my soul powers. It's not that they got weaker—it's that they've returned to their true level. Demon Slayer is a lower-level world; what seems powerful there doesn't match the scale of One Piece. Put simply, what we see now is the actual strength these abilities should have. If I went back to Hunter x Hunter, it would probably be the same."
"I thought I'd already elevated Demon Slayer to a higher tier… but the gap is still this big."
He muttered to himself, then saw Dom open his eyes, clarity slowly returning to them.
Oboro put his hands in his pockets, tilted his head, and smiled. "Congratulations. You didn't die. And you're much stronger now."
Dom pushed himself up with his arms. He could feel he was different. He stared blankly at his own hands.
He had always been lean and relied entirely on speed and agility to survive in the Flame Dragon Pirates. He'd never considered himself strong. But now… he could feel raw, explosive power surging through every muscle and vein.
His senses had sharpened the most. Through the window, he could clearly see things far in the distance.
His hearing picked up conversations between marines walking outside. His sense of smell had also grown incredibly acute.
"My face…" Dom touched his forehead, his throat bobbing nervously.
In the world of One Piece, all powers and changes must fit within its established order.
There were already many races here: Minks, Longarms, Longlegs, Fish-men, Giants, and more. Charlotte Linlin's nation of Totto Land was proof of that diversity.
But now, using the system and resources he'd gathered elsewhere, Oboro had created something entirely new in this world.
The Demon Tribe.
A race that humans could transform into.
"What did you do to me?" Dom finally realized what had happened and looked straight at Long.
The system, the cards… none of these were visible to anyone else.
"Just made a few adjustments to your body. Don't overthink it. You just need to know you're stronger now—and that gives you a better shot at staying alive." Oboro turned around, sat on a chair, and crossed his legs casually.
"Are you… a Devil Fruit user?" Dom asked, putting the pieces together.
"You could say that." Oboro gave a vague answer.
Then, right before Dom's eyes, Oboro held out one hand. Out of nowhere, a weapon materialized. It looked like a short blade, crafted with exquisite skill and from materials far superior to ordinary steel.
Whoosh.
Oboro flicked his wrist and tossed it over. Dom caught it easily.
"For you."
It was a Nichirin Blade.
Though in One Piece, it wouldn't have any special properties. At most, it was sturdier and sharper than regular weapons. But compared to the junk Dom had been using, it was priceless.
Dom's eyes lit up with joy, but his mind was still reeling. He needed time to process everything.
He wanted to ask exactly what kind of power Oboro had… but thought better of it. They had only just met. They were together only out of necessity. Their relationship wasn't close enough for Oboro to share his secrets.
For several days, they stayed hidden inside, watching the marines' movements in the streets below.
Going without food or water was no problem for Long—he could slow his body's functions down to a minimum.
Dom, however, struggled. Even though becoming a Demon had removed his weakness to sunlight, other traits had changed. He no longer needed to eat flesh or blood, but he had lost the ability to grow stronger by consuming others. Now, just like any other living being here, he had to eat normal food to survive.
All these changes were unavoidable—so that foreign powers could fit into One Piece's natural laws.
"With your current strength… do you think you can take down the captain of the Flame Dragon Pirates?" Oboro asked suddenly.
"There's… a fair chance." Dom replied, confused why Oboro would ask this.
"Good." Oboro nodded, having made his assessment.
Truly worthy of this world, he thought. Even the natives have incredible natural strength and talent. Luffy and Ace are exceptional, but they're not the only ones. There are monsters everywhere.
The Flame Dragon Pirates' captain had a bounty of 15 million berries.
And the power from an Upper Rank Demon… it only brought Dom up to the level of a pirate worth around 10 million?
The way higher-level worlds forced adaptation was truly harsh.
Luckily… Oboro still had plenty of cards stored in his system inventory.
"The marines are leaving!" Dom spotted through the window that the large group of soldiers was finally withdrawing. A huge smile spread across his face.
They had safely made it through the danger.
____________________
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