Roy Amos, Lieutenant of Marine Headquarters, commander of the Detention Unit warship DT-31.
Rumor had it he was born in the West Blue. He joined the Marines at age twenty, making this his eighth year of service.
During his enlistment physical exam at a Marine branch, he performed only averagely. But after participating in the capture of the West Blue ability-user pirate "Giant Rhino Captain Tora," his strength suddenly skyrocketed—
which wasn't unusual; many Marine officers only start showing their sharp edge after encountering a formidable foe.
Afterward, he was specially recruited into Marine Headquarters, passed the HQ recruit assessment, and voluntarily applied to serve in the Detention Unit.
—That was everything the Detention Unit Marines thought they knew about Roy Amos.
But in truth, what none of them knew was—
Roy Amos' real identity was that of a visitor from another world.
However, there was something the Marines did get right.
Roy truly had his own sense of justice.
And that was—
"Ice-cold cola is justice!"
Roy declared happily as he devoured a slice of pizza and washed it down with chilled fizzy bliss.
At this moment, he was simply watching the hourglass on the table in front of him.
The last grain of sand fell precisely.
Then, in his ear—
[Paramecia – Strong-Strong Fruit has been added to the Fruit Encyclopedia. Current level: LV1]
The illusory light screen before him shifted.
It slowly transformed into an ethereal book.
On its pages were illustrations of various Devil Fruits.
[Paramecia – Cage-Cage Fruit – LV1]
[Zoan – Ox-Ox Fruit: Giant Rhino Model – LV1]
[Zoan – Dog-Dog Fruit: Dalmatian Model – LV1]
[Logia – Glint-Glint Fruit – LV1]
[Logia – Magma-Magma Fruit – LV1]
[Logia – Ice-Ice Fruit – LV1]
And on the newest page, [Paramecia – Strong-Strong Fruit – LV1] was just finishing inscription.
The book closed.
On its cover were four words: [Fruit Encyclopedia].
[Holder: Roy Amos]
[Current Devil Fruits: 19
(Paramecia – 7, Zoan – 7, Logia – 4, Special Paramecia – 0, Mythical Zoan – 1)]
[Fruit Slot Count: 2]
[Currently equipped: Ox-Ox Fruit: Giant Rhino Model LV1, Human-Human Fruit: Buddha Model LV1]
[Current Berries: 411.3 million]
"Finally! Nineteen Devil Fruits collected. Only one more to unlock the third fruit slot.
And this guy's Strong-Strong Fruit is actually quite useful!"
"This trip was definitely worth it."
Roy muttered to himself—words that only he could understand.
Because yes—
As a transmigrator, Roy had his own system.
The very thing he was looking at now: the Fruit Encyclopedia.
As the name suggests—this system was tied to the Devil Fruits unique to the world of One Piece.
The Fruit Encyclopedia had two main functions.
First function: Recording and Using.
As long as he got near a Devil Fruit user and spent some time with them, he could record their Devil Fruit into the Encyclopedia.
If the ability user demonstrated their power in front of him, the recording process sped up.
Once recorded, he could equip a Devil Fruit in a slot and use that fruit's ability himself.
He started with one fruit slot, and every ten fruits collected unlocked one additional slot.
Of course, if Roy directly obtained a real Devil Fruit—
If Roy obtained a real Devil Fruit himself,
he could absorb it and directly gain the LV3 version of that fruit's ability.
The Encyclopedia's second function was the enhancement of fruit abilities.
Once a fruit was recorded, its base level was LV1.
After that, Roy could spend enough Berries—or equivalent treasure—to permanently upgrade that fruit's ability level.
Alternatively, he could spend a much smaller amount to temporarily unlock a higher-level ability—
typically one-third of the normal cost, but the effect would only last one hour.
In addition, because Roy wasn't eating actual Devil Fruits…
His abilities were not restricted by seawater or seastone.
As for how Roy evaluated this golden cheat of his—
"Broken as hell!"
Yes.
He was fully aware: the Fruit Encyclopedia was terrifyingly powerful.
He could use multiple Devil Fruit abilities at once, without weakness to the sea or seastone.
That alone was a straight, unobstructed highway leading to the very top of the world.
And don't let a certain "Kaido-sensei" fool you with his
"Haki surpasses everything" nonsense—
he himself used the legendary Fish-Fish Fruit, Azure Dragon Model.
Which raised the real question:
Where could Roy safely obtain the most Devil Fruits?
For Roy, the answer was simple—
The Marines.
Backed by the World Government, holding back the Great Pirate Era from total chaos—
the Marines had the highest number of Devil Fruit users,
and had access to the highest variety of them too.
So Roy chose to join the Marines, and specifically the not-so-popular Detention Unit.
And it turned out he was right.
In eight years, through interacting with Marine ability users and occasionally escorting captured criminals,
he had collected nineteen different Devil Fruits.
These included even the Logia abilities of the current three Admirals,
and the Mythical Zoan Human-Human Fruit: Buddha Model used by Fleet Admiral Sengoku.
In terms of Devil Fruit stockpile—
Roy had built a very solid foundation.
Which left him with only one problem:
"I need a way to make money."
So thought the good Lieutenant Roy.
Because, as mentioned before, he needed Berries to upgrade fruit abilities.
The prices varied depending on the fruit,
but they all shared one thing in common—
The stronger the fruit, the more absurdly expensive the upgrades.
Based on Roy's observations:
Normal Paramecia / Zoan
LV2: ~50 million Berries
LV3: ~200–300 million
LV4: ~1 billion
LV5 (Awakening): tens of billions+
Logia Fruits were even more exaggerated.
Even a weaker one like the Smoke-Smoke Fruit:
LV2: 300 million
LV3: 1.5 billion
LV4: 5 billion
Awakening: 10+ billion
And top-tier Logias like the Magma-Magma and Ice-Ice Fruits cost far, far more.
...
Incidentally, Roy's monthly salary as a Marine lieutenant was about 300,000 Berries.
And in all eight years he'd been in the Marines—
even counting escort bonuses and mission rewards—
he had only managed to save a little over 40 million Berries.
"I'm a model citizen who doesn't smoke, doesn't drink,
and whose only hobby is drinking cola—
and it's STILL this hard to save money—hic!"
Roy hiccuped and sighed deeply.
He was genuinely troubled.
"I'm broke!"
Who could've guessed that the thing he worried about before transmigrating
and the thing he worried about after transmigrating
would be the exact same problem?
"If this keeps up, I'll just have to leave the Marines once I collect twenty Devil Fruits.
Becoming a bounty hunter isn't a bad idea. Lots of traveling, sure,
but the money is WAY better than Marine wages."
"And even though all my fruit abilities are still LV1 for now,
once I unlock the third fruit slot,
I'll have more than enough strength for the first half of the Grand Line."
Roy calculated internally.
But at that moment—
BOOM!
The ship suddenly shook violently, and shouts erupted from outside the cabin.
Roy instinctively protected his ice-cold cola.
"What the hell? Who's steering—
Hans! You bastard, are you trying to get fired!?"
Still yelling, he chugged the rest of his cola,
then pushed open the cabin door and stepped out.
Chaos greeted him on the deck.
Marines were shouting and firing their rifles.
They were aiming into the sea.
Under the moonlit night sky—
The shimmering waves parted as a massive creature rose from beneath the water.
A lion's head.
A fish's body.
Dozens of meters long.
Its huge eyes burned like embers in the dark.
"Lieutenant Roy! It's a Sea Beast—
a large Sea Beast is attacking us!"
Chief Petty Officer Fal rushed to Roy's side, reporting frantically.
"A Sea Beast?"
Roy arched a brow.
As a Marine escort ship frequently active in the Four Blues,
its underside was reinforced with seastone.
Normally, Sea Beasts and Sea Kings wouldn't even notice the ship.
But occasionally, accidents happened—
for example, if a near-shore Sea Beast or small Sea King swam too close to the surface,
it might detect this "big metal lump."
"Yes, sir! Looks like we've run into some terrible luck!"
Fal looked close to tears.
But—
"Terrible luck? What are you talking about? This is GREAT luck."
Roy cut him off:
"If I remember right, Sea Beast meat sells for quite a lot!"
"Wh—what?"
Fal couldn't process that.
But Roy didn't bother explaining.
"All units, cease fire!
If you damage the good cuts of meat, I'll personally throw you overboard!"
"???"
Every Marine on the ship froze.
But as soldiers, they instinctively obeyed the order and lowered their guns.
"Sir, you…"
Someone tried to ask a question.
But before anyone could speak—
Roy moved.
BOOM!
He bent his knees and launched himself upward!
The force was so immense that the entire ship visibly tilted.
Before the Marines' stunned eyes,
Roy's figure shot through the air toward the enormous Sea Beast.
"Lieutenant Roy!!!"
Their voices echoed in alarm.
Because the Sea Beast had clearly noticed Roy as well.
"ROAR!"
Its massive head rumbled with a deep growl, then lunged toward Roy with terrifying force.
"It's over!"
"If he takes that hit head-on… even the Lieutenant—!"
"Prep rescue teams! Prepare to rescue the Lieutenant!"
The Marines were completely panicking.
But in the very next instant, the sight before their eyes made their eyeballs bulge and their jaws drop so wide they nearly dislocated.
Under the moonlight—
The Marine Lieutenant soared across the sky, his coat with the word "Justice" fluttering behind him.
He bent his arm, tightening it—
—and clenched his fist!
In the pale moonlight, every Marine saw it:
His thick, iron-forged-looking arm.
A muscular arm knotted like solid steel.
[Currently Equipped Fruit - Slot 1: Ox-Ox Fruit, Model: Giant Rhino, LV1 — Weak Zoan ability. Grants the body of a giant rhino; physical toughness and muscle density far exceed normal humans.]
[Currently Equipped Fruit - Slot 2: Strong-Strong Fruit, LV1 — Weak Paramecia ability. Muscle strength increases fivefold.]
Everyone knew that Zoan Devil Fruits granted their users strong, beast-like bodies.
The gladiator Antolia also knew that the Strong-Strong Fruit massively enhanced muscle power.
But—
What would happen if someone possessed both a Zoan Fruit's enhanced physique and the Strong-Strong Fruit's muscle amplification?
The answer unfolded before them.
BOOM!
Roy threw his punch.
The force generated a violent gust, pressing down the sea beneath him so hard it carved out a massive "trench" across the surface.
A heartbeat later—
His fist collided with the Sea Beast's head.
And then, before every Marine's stunned eyes—
That enormous Sea Beast, easily over a hundred meters long…
was blasted backward by Roy's single punch!
"AOOO!"
It screamed, crashed back into the sea, and immediately lost consciousness.
Roy, meanwhile, landed atop the creature's head, while the Marines exclaimed:
"Eh—eh—eh—EH?!"
That was exactly why Roy wasn't panicking despite all his Devil Fruits still being only LV1.
Because—
"Combining Devil Fruit abilities is nowhere near as simple as one plus one.
If you understand enough fruits well enough, even a level-1 ability can unleash power far beyond imagination."
Roy whispered in his heart.
"And in this world…
no one understands Devil Fruits better than I do."