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One Piece: Jacket King

Reborn into the world of One Piece, Vesta Rex has big dreams of being a famous pirate one day. Finding himself in the same island as future Worst Generation members Eustass Kid and Killer, Rex dreams of finding the powerful Jiki Jiki no mi and becoming a Yonko. However, through a cruel twist of fate, he accidentally consumes the Jake Jake no mi instead, becoming a jacket human. But Rex refuses to let this turn of fate get him down. Vowing to become the strongest, despite his weak fruit, Rex sets off on a journey that will rock the ocean. His goal? “Ore wa rekusu! Sono Ō uwagi ni na kiru otokoda!” (I am Rex, the man who wears the King’s Jacket!) Disclaimer: cover photo is not mine

KingJoker · Anime & Comics
Not enough ratings
52 Chs

Reaper Island

(Two Days Later)

Reaper island was… not the best vacation spot in the Grand Line.

"Captain! The sulfur rising is starting up again!" Rose shouted out, causing Rex to widen his eyes in panic. Moments later, the ground of the island begins to tremble as numerous successive explosions go off underground.

"Again!?" Rex roared at the island in anger. "If you like sulfur so much, why don't you keep it for yourself?"

Unfortunately, the island doesn't respond, forcing Rex into a large, tightly packed igloo made of Monet's snow with Rose, Monet and Sugar. Moments after the four take cover, a massive plume of sulfuric gas rises up from numerous pores in the island.

"Friggin' climate change." Rex curses under his breath.

From Rose's initial studies, the island had been uninhabited for years. Still, there was a trace of a long dead civilization that Rose believed was wiped out by the poison around 50 years ago.

Ad for the source of the gas, the island possessed numerous underground water sources that had a plethora of bacteria. As for the sulfuric gas, every few hours, all the oxygen in the water would be used up, causing the bacteria to reduce sulfur instead.

The hydrogen sulfide would build up in the underground pockets until the pressure was too high and then it would auto-ignite causing an explosion that released sulfur dioxide into the air.

"Captain, might I make the suggestion that we get the hell off this island!?" Monet shouts, sick and tired of this death trap. "No amount of gold in the world is worth this much danger. Hell, no amount of anything in the world is worth this much danger."

For once, Rex can't help but agree. No amount of gold was worth braving this island. Unfortunately, in the first sulfur rising, Rex had lost Tiger, Kid, Jinbe and Hawkins, so he couldn't just leave the island without finding them.

"We find the rest of the crew, then we leave, and we burn that damned log pose." Rex announces.

Rex wished that he could kill the pirate group Kid had stolen the log pose off of, but Kid had already beat them. He would make sure to kill them a second time when he met them in hell.

"Rose-nee, why can't you just go sucky-sucky on all the gas?" Sugar asks Rose with a head tilt.

"It's called Poison Pink and the reason I can't use it on this gas is there is too much of it. I can maybe detoxify one of you if you breath some in, but with all this gas, it's just not feasible." Rose says with a dejected expression. The one island where her abilities should have been useful and she was still lagging behind.

"Don't worry about it Rose, I'm sure it'll all work out in the end." Monet says reassuringly. "Besides, we've got the captain with us. I just pity Kid's group. Kid's probably flipping out right now."

"STUPID POISON ISLAND!" Kid roars, trying to plug in all the gaps in his metal barrier where the gas was seeping in.

Hawkins was also helping out, predicting where some of the gas would leak in and blocking it up it up with straw.

"Remind me to educate the captain on the meaning of the words 'great peril awaits us on this island', so that next time we're not in this situation!" Hawkins shouts.

"Maybe you shouldn't have told him great wealth awaited him as well!" Jinbe grunts, holding down and opening with some cloth. "Your captain would never turn down a good dollar."

"You guys are only seeing the negatives! Look at the positives, this is a joyful adventure!" Tiger shouts out in glee, this island reminding him of his adventuring days.

"Joyful adventure huh?" Kid says with a grin. "Let's see how joyful you are after I kick you out of this shelter."

Tiger blanches, before shaking his head. "On second thought, I very much like this shelter."

With that, the two groups wait out the gas plume before leaving their respective shelters.

Rex takes a look around, seeing if Kid and his group had migrated into sight. Unfortunately, he still can't find them.

Even without the gas, the island is covered in a thick fog that makes it nigh-unnavigable. The temperature on the island was sweltering on account of the hot sulfur gases, meaning Monet's Diamond Dust was ineffective.

"Well, let's move to the only visible structure and hope Kid and his group are doing the same." Rex says, moving towards a massive mountain peaking above the fog bank.

The trio follow behind Rex, making sure to stick close. After all with the fog, only Rex's observation haki could detect any threats ahead of time.

Rex radiates vibrations to create a bubble of clear air in front of the group as they trudge forward through the barren wasteland.

Then, Rex suddenly freezes.

"Get back!" Rex shouts before a horde of massive insects comes charging at the group. From massive beetles to spiders to worms even flies, all of them come charging at Rex, glowing with a unique red hue.

Monet quickly forms a snow shelter while Rex leaps into battle. Bathing himself in a blue electricity, Rex's claws glow red hot as he grins. A low hum is emitted as Rex prepares to go all out from the jump.

"Is that all you've got island!?" Rex shouts before leaping into the fray, happy to vent some of his anger.

Rex's superheated claws rip through the insects' bodies like they were warm butter, ignoring their sturdy exoskeletons and melting their organs. Eventually, all that is left surrounding Rex are piles of insect corpses.

"Now, let's keep moving." Rex says, moving onwards to the mountain.

The sulfur insects don't let up on their assault though, with both Kid and Rex's group facing numerous attacks from them.

Through this, Kid discovers that water seems to be extremely effective on the sulfur insects as it turned the sulfur dioxide in their lungs into sulfuric acid and melted them from the inside. Jinbe and Tiger are also pleased to see that they can control this sulfuric acid, with Tiger creating many large vats of the acid to bring back to the Solar Wind.

Soon, the two crews make it to the mountain, arriving on different sides.

"What do we do now, captain?" Monet asks, still not finding Kid or his group.

"We scale the mountain." Rex says with a sigh, knowing that Kid would do the same if he were on the other side and they could then meet at the top.

As for walking around, there was no guarantee that that would work, especially since Kid could be wlaking in the same direction, leading to them circling the mountain meaninglessly.

"Captain, I wouldn't advise you to do that." Rose protested. "If we climb the mountain, it will be difficult to take cover from another sulfur rising or an insect attack. With the immense heat this mountain is radiating, Monet's igloo would be evaporated almost immediately.

Rex frowns, noticing that the temperature had indeed increased as neared the mountain. While Rex had long adapted to high heats, he notices that Rose, Monet and Sugar are drenched with sweat.

"Do you have another way to find them?" Rex asks simply, to which Rose shakes her head. "Then we scale the mountain."

Rex then begins his climb, tying a rope from himself to the other three. With his claws and his Faust-enhanced strength, Rex is able to scale the mountain with ease, reaching the top in a matter of moments. Then, he realizes just what this mountain is…

"Hawkins, are you sure?" Kid says, scaling the mountain with massive metal arms.

"Almost positive." Hawkins states with a frown. "I spent most of my life living on a volcano, and I believe this mountain is an active volcano, primed to erupt any moment now."

"Then we've got to get to the top as quickly as possible so we can meet up with the captain and get the hell off this death trap!"

Meanwhile, Rex was clicking his tongue as he looked down at the massive pool of Blue Lava sitting at the bottom of this volcano. Now, the ruins of the town seemed to make more sense.

Sulfur fires burnt blue, meaning this lava was likely saturated with dissolved sulfur. The volcano had probably erupted sometime in the past, spreading the sulfur gas through the island, poisoning the citizens and destroying their homes. After that, the sulfur-reducing bacteria had made their homes in the groundwater, causing the sulfur risings.

"Captain, the lava levels of this volcano are alarmingly high. I believe that we should leave this place immediately." Rose says.

Rex shakes his head. Kid still wasn't here yet. And what's more, Rex saw what looked to be a cave sitting just above the lava levels inside the volcano.

At first, Rex believed the treasure to be a hoax, but seeing the cave intrigued him. For someone to go through such means to hide a treasure, he was certain it had to be something good.

"Captain…" Monet says with a worried tone. "Get that smile off your face! We are not! I repeat NOT, going in there, under any circum-"

Boom!

The island trembles as the volcano begins to rock violently. Rex notices Kid and his group jumping up on the other side of the mountain.

The two lock eyes and Rex points to a cave beneath them. Kid grins and nods.

"Geronimo!" The two shout, both leaping with their groups in tow towards the volcano.

Then, through rocket thrust for Rex and magnetism for Kid, both of them launch themselves into the cave. Kid then rapidly seals it up with some metal before the two run deeper in, their crews in tow.

Moments after the metal is sealed the lava has already rushed in.

"Jakekeket! Doesn't this make you feel alive Kid!" Rex shouts out.

Kid only grins as the two rush off at their top speed, dragging their crewmates behind them.

Eventually, they come across a large chute, that leads both up and down. The crew jumps to the upper level as the lava runs back down through trenches built into the lower level.

With a sigh, Rex grins. His guess had panned out.

The other six crew members give Rex and Killer nasty looks as they finally catch their breaths.

"Come on, it was treasure!" Rex says with his arms held out in a 'what did you expect' position.

The crew just sigh out in exasperation, seeing that Rex had already run off to see the treasure he had gotten.

"Oh dear lord!" Rex cries out in surprise at what he had seen. "This changes everything."

(Several Hours Later)

Rex flopped down in his chair, having finished the journal that had come with the treasure. It was… a lot to decode.

"Captain, the implications of this research…" Rose said, flipping through the documents with excitement in her eyes. "This is miles beyond anything my father could accomplish."

Rex nodded.

The treasure they had found was manifold.

For one, there was a sizable amount of gold and other valuables in the hold, enough to make most of the crew's jaws drop to the floor. On top of that, there was a devil fruit Rex recognized as the Sara Sara no Mi: Model Axolotl and a skillful grade sword. It was the lifelong treasure of a long-dead pirate known as Bagoas 'Toxic King' Locusta.

From his journal, Rex learned that Locusta was once a famous pirate, with a massive fleet, comparable to the Donquixote Pirates in their prime. Locusta ate the poison devil fruit, Magellan's, almost a hundred years ago, using it for research and combat.

Locusta had mixed a rather potent sulfur-based poison into the volcano of a peaceful island and through a simulated eruption, he had killed all but a few islanders. The survivors were then experimented on by Locusta.

As for why he did this, Locusta had discovered that the gas he released, dichlorodiethyl sulfide, was effective in creating mutations in human beings.

Unfortunately, Locusta had been sought out by Rocks D. Xebec, who massacred most of his fleet and had forced him to join the Rocks pirates. Locusta had agreed but had never revealed the location of his treasure to Rocks.

Rocks was apathetic to this, as his goal was to topple the World Government and was apathetic to treasure or other matters. Unknown to Rocks, Locusta had long been using this island to conduct scientific research.

As for the subject of this research…

"Captain, if we can synthesize more of this SAD chemical that Locusta was researching, it could have all sorts of uses." Rose said joyfully.

Indeed, Locusta had discovered the SAD chemical. It was not all that surprising to Rex given the fact that he had found Smiley's devil fruit there, but it was a great piece of news.

Rex had concluded that at some point in the future, Caesar Clown would come to this island, using his Gasu Gasu no Mi to make it to the cave where he would discover the SAD chemical. Then, using the sulfuric gasses, Caesar had likely created his weapon to create a similar atmosphere on Punk Hazard, making the island prepped for his research.

After that, Caesar used his knowledge from MADS and the SAD chemical to create his numerous technologies from SMILEs to gigantification.

But now, that chemical was in Rex's hands.

"Rose, how soon until you can start synthesizing some of this SAD chemical." Rex asked, wanting to get a jump on the research. It had taken Caesar at least four years to discover SMILEs. Rose was much less experienced so it could easily take twice as long for her.

"With all the scientific equipment we recovered from the island, I should be able to start the moment Kid repairs it. I might even start making some headway on the Germa technology." Rose explains.

Rex grins. This was a very important discovery.

(AN: Hey all, this is my attempt at an Pseudo-OC island, tell me what you think. Also, yeah, I sort of cheapened Ceaser Clown, but I felt like the discoveries credited to him were a bit much given that he's allegedly <<< Vegapunk in science.)