Roy Amos, Marine Headquarters Lieutenant, commander of detention force warship 'DT-31'.
Supposedly hailing from the West Blue, he joined the Marines at age twenty—eight years ago now.
His performance in the branch recruitment physical tests was unremarkable, but after participating in the capture of West Blue ability-user pirate 'Giant Rhino Captain Tora,' his strength began improving by leaps and bounds—not unusual, really. Plenty of Marine officers only started showing their potential after facing a particularly tough opponent.
Afterward, he was specially recruited into Marine Headquarters and, after passing the HQ boot camp evaluation, voluntarily requested assignment to the detention force.
—This was what the detention force members knew about Roy Amos.
But the truth that nobody knew was...
Roy Amos's real identity was actually that of a visitor from another world.
However, there was one thing the Marines had gotten right.
Roy truly did have his own sense of justice.
"Ice-cold cola is justice!"
Roy sighed contentedly as he sent a slice of pizza and a gulp of ice-cold happiness down his throat.
At this moment, he was simply watching the hourglass on the table before him.
The last grains of sand had just fallen.
And in his ears...
[Paramecia-type: Muscle-Muscle Fruit has been added to the Fruit Encyclopedia, current level LV1]
As this voice echoed, the translucent screen before him transformed.
It gradually shifted into the form of an ethereal book.
At this moment, the book's pages displayed Devil Fruits of various shapes and appearances.
[Paramecia - Cage-Cage Fruit - LV1]
[Zoan - Ox-Ox Fruit: Giant Rhino Form - LV1]
[Zoan - Dog-Dog Fruit: Dalmatian Form - LV1]
[Logia - Glint-Glint Fruit - LV1]
[Logia - Magma-Magma Fruit - LV1]
[Logia - Ice-Ice Fruit - LV1]
On the newest page, [Paramecia - Muscle-Muscle Fruit - LV1] had just finished recording.
The pages closed.
On the cover, four words were written: [Fruit Encyclopedia].
[Owner: Roy Amos]
[Current Encyclopedia Fruit Types: 19 (Paramecia - 7, Zoan - 7, Logia - 4, Special Paramecia - 0, Mythical Zoan - 1)]
[Fruit Slot Quantity: 2]
[Currently Equipped: Ox-Ox Fruit: Giant Rhino Form LV1, Human-Human Fruit: Great Buddha Form LV1]
[Current Berries Held: 41,130,000]
"The Fruit Encyclopedia finally has nineteen Devil Fruits collected... just one more fruit until I unlock the third slot, and this guy's Muscle-Muscle Fruit is actually pretty useful!"
"This trip was worth it."
Only Roy could understand what he was muttering to himself at this moment.
That's right.
As a transmigrator, Roy had his own system.
That was the 'Fruit Encyclopedia' he was currently viewing.
As the name suggested—this system was related to the One Piece world's unique product: Devil Fruits.
The Fruit Encyclopedia itself contained two core functions.
The first function was collection and usage.
As long as he spent time near a Devil Fruit user, he could record that person's Devil Fruit into the encyclopedia.
When the ability user demonstrated their power in his presence, the recording speed increased significantly.
Once he obtained an ability, he could use the corresponding Devil Fruit power through the fruit slots in the encyclopedia.
There was only one fruit slot at the start, with an additional slot unlocking for every ten Devil Fruits collected.
Of course, if Roy directly obtained an actual Devil Fruit, he could absorb it and immediately gain that Devil Fruit's LV3 level ability.
The encyclopedia's second function was fruit ability enhancement.
After a fruit was recorded in the Fruit Encyclopedia, its base ability level was LV1.
Roy could then strengthen and upgrade his fruit ability levels by spending sufficient berries or equivalent treasure.
Additionally, Roy could spend a smaller amount of treasure to temporarily unlock a certain level of fruit ability—the required treasure was roughly one-third of a permanent unlock, but only lasted for one hour.
Furthermore, seemingly because Roy hadn't actually eaten a Devil Fruit, the fruit abilities he gained weren't constrained by seawater or Seastone.
As for his assessment of this golden finger...
"Broken!"
That's right.
He clearly understood just how terrifying the Fruit Encyclopedia's effects were.
It let him use multiple Devil Fruit abilities without fear of seawater or Seastone.
This was basically a highway straight to the top of the world.
Never mind Kaido-sensei spouting stuff about 'Haki transcending all'—the guy himself was a user of the legendary [Fish-Fish Fruit: Azure Dragon Form], wasn't he?
So the question became:
Where on these seas could one most safely obtain a large quantity of Devil Fruits?
For Roy, the answer was simple—the Marines.
As the massive force backed by the World Government that kept the Great Pirate Era from completely spiraling out of control, the Marines naturally had the highest number of ability users, as well as the most opportunities to encounter them.
So Roy chose to join the Marines, and deliberately selected the unpopular 'detention force.'
And the facts proved his choice was correct.
Over these eight years, through contact with ability users within the Marines and occasionally transporting criminal ability users, he'd already obtained a full nineteen Devil Fruit abilities.
These even included the Logia fruits of the current three Admirals, as well as Fleet Admiral Sengoku's Mythical Zoan [Human-Human Fruit: Great Buddha Form]—top-tier Devil Fruit abilities.
It could be said that in terms of fruit ability accumulation, Roy had already built up a decent foundation.
So now, he only faced one problem.
Namely...
"I need to figure out how to make money."
The Marine Lieutenant thought to himself.
Yes.
As mentioned before, his fruit abilities required berries to enhance.
The specific prices varied wildly depending on the fruit type, but they all shared one characteristic—the stronger the fruit, the more expensive it was.
Based on Roy's current analysis, ordinary Paramecia and Zoan fruits required around 50 million berries to strengthen to LV2, 200-300 million for LV3, 1 billion for LV4, and fruit awakening at LV5 generally required over several billion berries.
Logia fruits were even more outrageous—the ordinary Smoke-Smoke Fruit needed 300 million berries just to reach LV2, LV3 required a whopping 1.5 billion, LV4 needed 5 billion, and fruit awakening was an astronomical figure exceeding 10 billion.
As for top-tier Logia fruits like the Magma-Magma Fruit and Ice-Ice Fruit, their enhancement prices were even higher.
Incidentally, Roy's monthly salary as a Marine Lieutenant was around 300,000 berries.
And in his eight years with the Marines, even counting prisoner transport stipends and bonuses, he'd only managed to save up a little over 40 million berries.
"I don't smoke, don't drink, and my only hobby is sipping some cola, and even I can barely save money... burp!"
Roy burped and sighed.
This genuinely gave him a headache.
"No money!"
Who would've thought that before and after transmigrating, he'd be worrying about the exact same thing?
"If push comes to shove, I'll just have to leave the Marines after collecting 20 Devil Fruits—become a bounty hunter or something. Sure, I'd have to travel around constantly, but at least the money comes in way faster than in the Marines."
"And even though all my fruit abilities are currently LV1, if I can unlock the third fruit slot, I should be fine in at least the first half of the Grand Line."
Roy calculated in his mind.
But just then...
"BOOM!"
The cabin suddenly began shaking violently, and shouts erupted from outside.
Roy quickly protected his ice-cold cola, bellowing, "What's going on? Who's at the helm... wait—Hans! Are you trying to get fired!?"
While shouting, he downed the rest of his cola in one gulp, then pushed open the cabin door.
He was greeted by a chaotic deck and Marines firing their rifles.
They were aiming toward the sea.
Under the moonlight of the pitch-black night sky, on the shimmering ocean surface, a massive creature was emerging from beneath the waves.
It had a lion's head, a fish's body, and was dozens of meters long.
Those enormous eyes burned like flames in the darkness.
"Lieutenant Roy, it's a Sea Beast—we're under attack by a large Sea Beast!"
Sergeant Farr rushed up to Roy, reporting urgently.
"A Sea Beast?"
Roy raised an eyebrow.
As a Marine unit that regularly operated in the Four Blues, the detention force's warships naturally used Seastone technology on their hulls.
So under normal circumstances, Sea Beasts and Sea Kings wouldn't detect the warship's presence.
But occasionally there were exceptions—like when a coastal Sea Beast or shallow-water small Sea King came too close to the surface and spotted this 'iron lump.'
"Yes! Our luck seems pretty terrible."
Farr looked ready to cry.
However...
"What do you mean terrible luck? This is great luck!"
Roy cut him off. "Sea Beast meat sells for a fortune, doesn't it?"
"...Wh-what?"
Farr didn't quite process that.
But Roy didn't answer him. "Everyone, cease fire—if you damage the prime cuts, you're all dead meat!"
"?"
Every Marine on the warship froze in confusion.
But as soldiers, they instinctively stopped shooting.
"Sir, you..."
Someone started to ask something.
But before they could finish, they saw Roy move.
"BOOM!"
He bent his knees, then... launched himself into the air!
The tremendous force actually made the entire warship visibly tilt at that moment.
Under the gaze of all the Marines, Roy's figure rapidly flew toward the massive Sea Beast.
"Lieutenant Roy!"
The Marines cried out in alarm.
But the next moment, their cries turned into horrified screams.
Because at that moment, the Sea Beast clearly noticed Roy too.
"ROAR!"
Its massive head let out a low growl before charging at Roy with tremendous force.
"We're screwed!"
"If he takes that head-on... even the Lieutenant..."
"Prepare rescue operations immediately! Get ready to save the Lieutenant!"
The Marines were practically panicking.
But in the very next instant, what they witnessed made their eyeballs nearly pop from their sockets, their jaws dropping almost to the point of dislocation.
Because at that moment, under the moonlight, the Marine Lieutenant streaked past, his coat emblazoned with 'JUSTICE' billowing in the wind.
He bent his elbow, then... clenched his fist!
In the moonlight, every Marine saw his thick, iron-cast arm!
The muscles beneath rippled like steel cables.
[Currently Equipped Fruit-1: Ox-Ox Fruit: Giant Rhino Form LV1 - Minimal fruit effects, grants giant rhino physique, body strength and muscle density far exceed normal humans]
[Currently Equipped Fruit-2: Muscle-Muscle Fruit LV1 - Minimal fruit effects, grants 5x muscle strength amplification]
Plenty of people knew that Zoan Devil Fruits could grant their users powerful, beast-like bodies.
Gladiator Antoria also knew his Muscle-Muscle Fruit could significantly enhance an ability user's muscles.
But what if someone simultaneously possessed both the base physical capabilities provided by a Zoan Devil Fruit and the muscle amplification provided by the Muscle-Muscle Fruit... what would happen?
This moment was the answer to that question.
"BOOM!"
Roy threw his punch!
The tremendous force created a gale that carved a massive 'trench' in the sea before him.
In the next instant, fist met Sea Beast skull.
And so, all the Marines witnessed it.
That massive, hundred-meter-long Sea Beast... was actually sent flying backward by Roy's single punch!
"AHHH!"
It let out a pitiful cry before crashing into the sea surface and immediately losing consciousness.
Roy's figure landed atop the Sea Beast's head amid the Marines' chorus of "EHHHHH!?"
That's right.
This was why Roy wasn't particularly anxious despite all his fruits still being at LV1.
Because...
"Stacking Devil Fruits isn't as simple as one plus one—as long as you have sufficient understanding of enough Devil Fruits, even LV1 abilities can produce unimaginable power!"
Roy murmured to himself.
"And in this world, no one understands Devil Fruits better than me!"