One Piece: Mystery Box System

[A/N: This chapter is a pretty long one, I thought about chopping it up but decided against it. Let me know what you think!]

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Scanning through the list of items he had received, for the first time in what felt like ages, something called hope began to resurface within Vin. 

He hurriedly accepted the rewards, moving them into his inventory as if he was afraid they would disappear the next second.

Pulling up his panel, he glanced at the new changes. 

[Mystery Box System]

[Current Universe: One Piece]

[Creator: ?&#Y&@Y#293]

[Holder: Vin]

[Age: 18]

[Total Box Count: 0]

[Boxes Held: None]

[Abilities: None]

[Inventory: Bag of 100,000 berries, Hito Hito no Mi, Model: "Kokuryū" (Black Dragon), Observation Haki (Beginner), Dimensional Travel Ticket to the Marvel Cinematic Universe (2008) ]

[Strength Rating: Civilian Teen]

'Finally... FINALLY!' he inwardly screamed. 

His perseverance had paid off, and the system had rewarded him. 

Vin's chance had finally come. 

A mythical Zoan devil fruit, one of the rarest and strongest types of devil fruits in the one piece world. 

On top of that, a dragon type. 

Vin was definitely satisfied with the result of his mystery box draw. 

With this devil fruit alone, he now had the capacity to change his current predicament and even carve out a place for himself in this world he now found himself in.

Next, his eyes moved to the other items.

He quickly glanced over the 100,000 berries, it was useful but not at the moment. 

Observation haki, another big pull. Though, the devil fruit definitely overshadowed it a bit. 

Finally, he glanced at the last item in his inventory. 

[Dimensional Travel Ticket to the Marvel Cinematic Universe (2008)]

'Interesting... but I'll have to look into that when I have time and aren't being held captive.'

Focusing on the panel, he noticed that all the items except the haki had a [Physical] tag next them indicating they were objects he could bring out or store in his inventory. 

Observation haki, on the other hand, had a [Consumable] tag indicating he could directly use it and integrate it into his person. 

Vin wished he could use the devil fruit right now, break out of his prison and slaughter the pirates but it seemed he wasn't able to do so... yet. 

With his arms bound, summoning anything physical wouldn't work.

He would have to wait until he was given freedom, probably when one of these drunkards wanted another errand ran. 

'In the mean time,' he glanced towards the observation haki.

'Nothing is stopping me from activating you,' As he thought to himself, he mentally willed the system to activate the observation haki he had obtained.

[Would you like to use 'Observation Haki (Beginner)' ? | Yes | No]

The second he selected yes, Vin felt as if a shackle had been released within his mind. 

Closing his eyes, he felt the world around him slowly open up as his senses expanded to a radius of about twenty meters around him. 

He was able to detect the presence of every single member of the crew. 

'thirteen...' Vin thought to himself, confirming with the number he had in memory. 

Not just presence, he could even feel their emotions: euphoric, annoyed, anxious.

Vin was broken out of his thoughts as he sensed a crew-mate walking in his direction. 

He immediately closed the system panel, and kept his eyes closed, pretending to be asleep. 

It didn't take long for the pirate to arrive next to him. 

"Hey, brat, wake up!" a gruff voice called out, followed by a sharp kick to his side.

Ugh.

Despite having obtained observation haki, that didn't change the fact Vin was still immobilized. 

All he could do was shift his body just enough to soften the blow, which he did.

The drunk pirate didn't seem to notice, his slurred voice carrying on. "Go clean the bathroom. It's a mess... hahaha."

He unsheathed a dagger from his waist, crouching clumsily as he hacked at the ropes binding Vin. After a few rough cuts, the ropes fell loose.

"Yea," Vin muttered, slowly rising to his feet as he removed the restraints that previously bound him... and never would again. 

For a moment, he considered taking his chance right then and there, but he held back. It was better to wait and use the opportunity given to him.

He began walking towards the location of the bathroom. 

Luckily for him, it was in a secluded location near the stern, perfect for him to summon and consume the devil fruit. 

Even though the pirate ship was small, about twenty-five meters long, that meant he would have to pass through the main deck where a majority of the pirates were currently hanging. 

Bracing himself, he continued walking. 

It didn't take long for his worries to be confirmed. 

"Yo! It's pretty boy! You ready, pretty boy? We're about a day away from Sabaody. From there, your life's gonna change," a pirate with a large gash on the right side of his face called out, grinning as he slapped down a card on the table.

"You better sell for a good price, or I might just buy you back and kill you myself," he sneered.

"HAHAHAHA!" The table of pirates erupted into laughter, their eyes briefly turning toward Vin as he walked past.

Vin tried his best to ignore them as he continued walking towards the bathroom. 

That was until he heard one of them speak up. 

"God, I hate that look in his eyes. It's been a month and he still think's he's gonna break free. "

*Scoff*

"Wishful thinking."

The voice came from a shorter, stocky pirate with a beady face and a crooked grin.

A few others around him chuckled, nodding in agreement.

Vin already knew what was coming. 

He didn't need Observation Haki to predict it. He'd lived through it too many times.

One of the pirates closest to him suddenly lashed out with a sudden kick aimed at his legs.

Although he sensed he could easily dodge it, he knew he had to take it. He had to play the part he'd been forced to play for the past month. 

'Just one last time,' Vin mentally told himself while bracing for impact.

Thwack

Thud

The kick hit clean, knocking Vin off his feet.

He used his hands to control the fall, easing his descent just enough to avoid injury. But he still slapped the deck with his arms and hands, making it look like he hit hard.

Vin readied himself for the subsequent beating that usually followed.

Though, this time...

"ENOUGH!" a thunderous voice boomed from the captain's chambers.

"There's only one day left 'til we arrive. I don't want any of your damn egos messing with our profit!"

"Yes, Captain Greska!" the pirates shouted back, their voices disjointed but loud enough to be heard.

The tension lingered for a moment longer before the pirates that had begun to gather backed off, grumbling under their breath.

Vin, meanwhile, had already pushed himself up and limped toward the bathroom, feigning injury and ignoring the stares from the crew — and the eyes of Captain Greska.

Greska's gaze lingered on Vin's figure as he shuffled away, contemplating.

The unease in his chest these recent day's hadn't faded. 

Lately, he'd been waking up in a cold sweat, haunted by a feeling he couldn't shake. The only thing he could maybe tie it to was the fact that they were transporting a slave. 

In fact, Grezka rarely participated in such activities.

He knew that if he sold the wrong person, his life could be over before he even realized his mistake.

Still, this one had shown up on his doorstep, practically begging to be sold.

"Ah, whatever," he muttered, shaking his head. "Stop being a coward, Greska."

"Hezka would laugh at me right now. Ha ha," he chuckled to himself as he returned to his chamber.

"It's probably just Sabaody," he sighed, laying down on his bed. "Too many monsters show up here. Plus... it's close to Marie Jois and Marine Ford. We need to be careful. "

Back on Vin's side, he had already arrived at the ship's bathroom, cleaning supplies in hand. One whiff of the air told him all he needed to know about what was in there. 

Luckily, this corner of the ship offered enough cover.

Placing the supplies down, he quickly pulled up the panel and summoned the devil fruit he had won.

Hito Hito no Mi, Model: "Kokuryū" (Black Dragon)

The second Vin held onto the fruit, his eyes were drawn to its beautiful and unique structure. 

It had a dark, scale-pattern and was shaped like a twisted pear fruit. Its surface marked with swirling black and violet dragon-like ridges, emitting a faint, ominous glow.

Snapping out of his stupor, Vin shot a quick glance toward the main deck, confirming nobody was coming.

He didn't know exactly what abilities this fruit would grant him, but he just hoped they wouldn't disappoint.

"Alright, it's now or never." He muttered, as he brought the fruit to his mouth.

In one swift motion, he took a solid bite and quickly tossed the rest into the ocean. 

He knew from memory that only a single bite was needed to gain its power, and there was no way he was going to subject himself to more than that.

Sure enough, the terrible taste hit him as soon as he took the bite.

Rancid

Putrid

Those were the only words that came to mind as his face twisted in disgust.

Fighting the urge to gag, Vin forced himself to chew and swallow the chunk he'd bitten off. Every second of it felt like a punishment, but he eventually got it down.

Vin panted slightly as sweat beaded down his face. 

He was just about to catch his breath when a sharp, searing heat began to spread through his chest.

At first, gentle, but quickly becoming something much more intense. 

Vin's vision began to blur, his muscles tensing involuntarily as if under immense strain. He could feel changes occurring to his body, his bones and muscles expanding and extending. 

The pain suddenly hit him all at once, causing him to lose consciousness, his body hitting the floor with a thud. 

Thankfully, due to the crashing waves and loud pirates, nobody noticed the noise, saving Vin from being discovered by the crew while undergoing his metamorphosis. 

If any one of them were to walk by they would definitely discover the anomaly.

Vin's body was growing significantly.

Even laying there on the floor, it could be seen his height had already increased from the previous two meters to three, and was still going. 

His previous skinny and malnourished frame was somehow growing larger and more robust. 

If Vin could see this from the outside, he would comment how it looked like Captain America before and after the super solder serum. 

The transformation took about four minutes to complete, and in that time, no one came to check on him. But Vin remained unconscious the entire time.

Another two passed, his body still sprawled on the floor next to the bathroom.

His clothes, now shredded by the force of his growth, hung awkwardly from his much larger frame.

Though, it had its own charm to it kind of like Gon when he went full power. 

Suddenly, through the loud shouts of the pirates, one voice cut through the noise.

"Oi, where's that brat? It's been a while, I don't hear or see him."

It was the short, stubby pirate from before — the one who hated Vin the most. His tone was sharp, laced with irritation.

"Exactly! I was just thinking that. I need him to come massage my feet real quick. Ha ha!" another pirate chimed in, earning a round of laughter from the others.

The stubby pirate, already angry after losing a game, slammed his cards down and stood up from his seat. His eyes locked on the path Vin had taken, he began marching toward it.

"That brat… I'll give him a couple of good licks. I won't hurt him too much," he muttered, licking his lips like he was about to enjoy it.

"Oh no, Ripper's up and moving. I feel bad for that kid," one pirate said, shaking his head.

"Ripper, don't overdo it," another pirate warned, his voice lazy as he leaned back in a chair, sipping a bottle of sake. "You don't want the boss on your ass."

"Yeah, yeah," Ripper waved his hand dismissively but slowed his pace a little.

As he approached the bathroom, the first thing he noticed was the smell.

"This brat... did he not clean it? I swear, I'm gonna—"

His words stopped cold. His eyes locked on a pair of feet sticking out from around the corner.

Curious, he stepped forward, but the sight that greeted him left him frozen.

It was Vin, but much bigger and larger than he ever was before. 

Even by just looking at him on the ground, the man could tell Vin was a giant compared to himself. 

Confused and shocked, he was about to turn around and call for his crew when he finally glanced at Vin's face. 

His eyes were open.

Frightened, he jumped back, quickly yanking a throwing knife from his pouch and hurling it at Vin's motionless body.

At the same time, he hurriedly shouted for his crew mates.

"OI! GET OVER HERE!"

Looking back at Vin, he noticed his eyes were now closed, completely still as if unaware of the knife flying straight toward his chest.

The man hesitated for a moment, doubt creeping in. "Did I really see him open his eyes?" he wondered. But it was too late now — the knife was already in motion.

1 meter.

0.5 meters.

0.2 meters.

Just as the blade was about to pierce him, Vin's body moved.

With a sudden jolt, his arms shot out, gripping the floor as he yanked himself to the side. The knife zipped past, missing him by inches, burying itself into the wood with a dull thunk.

Vin's eyes snapped open, but he understood there was no time to process the changes he felt had occurred in his body

His Observation Haki had jolted him awake, triggered by the surge of malicious intent radiating from Ripper as he approached.

Groggy at first, he still managed to react in time, narrowly dodging the knife.

Pressing a single hand against the floor, Vin pushed off with ease, leaping to his feet like an acrobat.

He now stood face-to-face with Ripper, who stared up at him, dumbstruck at the towering difference between them, not to mention the fact he had dodged that knife at pointblank range. 

Vin glanced down at his hands, now noticeably larger than before. His fingers were thicker, his palms rougher, and his nails sharper, like small claws.

He stretched his arms, cracking his knuckles one by one.

The strength coursing through him was overwhelming, far beyond anything he'd ever felt before.

It felt like he could crush a thousand of his former selves without even trying.

The feeling was slightly intoxicating. 

His gaze drifted back to Ripper, his eyes calm. Ripper noticed, his eyes darting to the side calculating how fast he could run.

"What's wrong?" Vin asked, his voice deeper than he expected it to be.

Ripper's breath caught in his throat, his feet slowly retreating step by step.

"Vin, listen... I was just messing around, alright?" Ripper said, his voice shaky as he took another step back.

"Listen, I won't say a word, I swear! I'll even help you escape."

Ripper's voice cracked with desperation as he raised his hands, palms up in surrender.

"No, wait — I'll help you take down the captain! Yeah, that's right! You can have it all — the ship, the crew — just... just don't hurt me!"

Before the last word had even left his mouth, Vin was gone.

Vanishing from sight, reappearing next to Ripper like a ghost.

Ripper's eyes widened, but by the time he realized it, it was too late.

Vin's hand shot out, grabbing Ripper by the head. In a single motion, he slammed him into the floor with a thunderous crack.

The wood beneath them splintering, the entire ship seeming to jolt from the force.

Ripper's muffled scream was cut short as his head pierced through the floor, his body going limp instantly as blood begin pool around him. 

Vin stood over him, his chest rising and falling steadily, his sharp gaze locked on the unconscious pirate below.

"Time for revenge..."