A little bit of AU, Some characters personallity and power might not match with their canon counterpart...
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Shells Town, East Blue
"This must be it—the Marine base where they're holding Zoro."
A young man with waist-length silver hair and a cold, sharp face walked toward the base's gates.
A crescent moon was marked on his forehead.
When he reached the front gate, he scoffed.
He drew the four-foot-long sword from his hip and with a single swing, a blade of light shot out and sliced the massive steel gate to pieces.
With a deafening crash, metal scraps flew everywhere and dust filled the air.
Inside the base, the loud noise startled a green-haired man tied to a post.
He stared toward the gate.
As the smoke cleared, a tall handsome man in white clothes walked through the wreckage.
The silver-haired man, Ray, walked right up to the tied up man.
"You're Roronoa Zoro, right?"
Zoro eyed him suspiciously. "Who are you? What do you want?"
"I'm here to save you."
"Save me? Why?"
Ray didn't answer.
Instead, he swung his sword again, slashing through the ropes holding Zoro.
Then he tossed Zoro's three swords over to him.
Just then, Marine patrols spotted the commotion and the base alarm started blaring.
"Warning! Intruders at the execution grounds! They're trying to free Roronoa Zoro! All marines, get to the execution grounds now and take them down!"
…
The piercing siren echoed across the entire island.
On the streets, people who were shopping, running stalls, or just playing around all scrambled back to their homes, locking their doors and windows tight.
One kid who wanted to go see what was happening got dragged back inside by his parents for a good spanking.
After living under the Marines' thumb for so long, the townspeople were terrified of getting caught in the crossfire.
Captain Morgan was a complete tyrant.
If they didn't lay low, he'd find any excuse to throw them in jail or hit them with a massive fine.
"Honey, who in their right mind would cause trouble for Morgan?" a woman whispered inside her home.
"Quiet! Don't even say his name—you never know who's listening," her husband hissed back.
"Fine, I won't. God, you're such a coward."
The husband took a long drag from his cigarette.
"My older brother said one bad thing about the Captain while he was drunk. Someone snitched, and they threw him in prison. We never saw him again."
The wife's face flushed with anger.
"That Morgan is a monster!"
"Hey! Be careful what you say!"
"Hmph. Coward," she muttered.
"I just hope whoever is crazy enough to attack the base today gets away safe."
…
At the tavern in the middle of town, a little girl named Rika was ecstatic.
She watched a distant figure with a straw hat running toward the base and giggled.
"Hehe, someone besides Luffy is trying to save Big Brother Zoro!"
"Good people always get help in the end," the tavern owner said, smiling as she patted Rika's head.
Both of them looked relieved.
For a little girl like Rika, stories about good people helping each other were always inspiring, no matter how they ended.
…
At the Marine Execution Ground
"Quick, spread out! Surround them!" a marine lieutenant commander yelled.
Dozens of Marine soldiers fanned out, cornering Ray and Zoro.
Just then, a boy in a straw hat launched himself onto the scene.
"Shishishi! Look what's happening! This is getting interesting!"
"Koby, let's go join the fun!"
"L-Luffy-san, I don't think that's a good idea!"
"Gum-Gum Rocket!"
With a whoosh, Luffy shot himself right into the middle of the execution grounds.
"Fire!" the lieutenant commander ordered.
Dozens of guns opened fire on Ray and Zoro.
Zoro tensed up; even he couldn't just ignore a bunch of guns.
Suddenly, Luffy flew in front of them.
The bullets hit his body, but instead of hurting him, they just made his skin stretch like rubber before bouncing off.
"Whoa, what is this guy?" Zoro's eyes nearly popped out of his head.
"Shishishi! I'm a rubber man. Bullets don't work on me!" Luffy grinned, having blocked all the shots.
He then turned to Zoro.
"Hey, Zoro! Wanna join my crew?"
"That kid with the chin-strap told me the Marines were going to execute you tomorrow anyway," Luffy added.
Hearing that, Zoro finally understood.
It didn't matter if he kept his promise; the Marines were never going to let him go.
The soldiers started freaking out, terrified by Luffy's strange power.
"Don't panic!" the lieutenant commander shouted.
"Captain Morgan will be here any second!"
Ray didn't seem to care one bit.
…
Two months ago, Ray had been dropped into the world of One Piece and got a system that let him copy characters.
The first card he drew was Sesshomaru, the Great Demon from Inuyasha.
He got Sesshomaru's natural abilities, like a super-sharp sense of smell and the power to coat his attacks with demon poison.
He also got Sesshomaru fighting skills and insane good looks he never had before.
After transmigrating, he ran into a bunch of small-time pirates.
They were no problem to deal with, but he noticed something weird.
Every pirate he beat, whether they had a bounty of millions or were just nobodies, would always scream that they worked for "Buggy the Clown" before he finished them off.
From what he gathered, Buggy had somehow become the big boss of the East Blue.
Rumor was, even Smoker couldn't handle him.
Everyone seemed terrified of the guy, and it felt like more than just luck.
Ray realized this version of the One Piece world was way different from the story he knew, and a lot more dangerous.
As the two months went by, Ray found that the more he acted like the cold and noble Sesshomaru, the higher his sync rate with the character would go.
As the rate went up, he unlocked new skills.
Poison Claws: A claw attack laced with a poison strong enough to melt steel.
Light Whip: A whip of energy that shot out from his fingers.
He also got Sesshomaru's legendary sword, Tōkijin.
His current sync rate was 39.9%.
But when he hit that number, he realized just acting the part wasn't enough to raise it anymore.
The system told him he needed to defeat a major boss tied to a big event in the One Piece story to break through the limit.
So, after checking the timeline with the system, Ray came to Shells Town to find Zoro, hoping to raise his sync rate.
Now that Luffy had shown up, everything was falling into place.
…
"You damn brats! How dare you cause all this trouble! Are you trying to start a rebellion?"
A huge guy with a metal jaw and a giant axe stomped onto the scene, an officer's cape flowing behind him.
"Are you telling me you're actually fighting back against me, the great Captain Morgan?" he bellowed, glaring at the three of them.
"Who's the one who started this mess? Step forward!"
The lieutenant next to him immediately pointed at Ray.
Morgan roared, "A pretty boy like you? You think you can mess with me? Do you have any idea what happens to people who cross me?"
Ray didn't even blink.
He calmly sheathed his sword, Tōkijin.
Ignoring Morgan's threats completely, he glanced at Luffy and Zoro, then turned and started walking toward the busted gate.
Luffy watched him, fascinated by how bold he was and let out a big laugh.
Then, puffing out his chest like he was imitating Ray, he grabbed Zoro and started walking out too, not paying the Marines any mind.
Zoro just tightened his grip on his swords while keeping a sharp eye on Morgan.
…
Being completely ignored made Morgan finally snap.
He let out a furious roar, raised his axe and charged at Ray, who was the closest to him.
"I'll chop all three of you into dog food!" he screamed.
The giant axe was about to come crashing down, but Ray didn't even flinch.
Everyone else watched, holding their breath.
Not a single emotion showed on Ray's handsome face.
But in his mind, he had already decided Morgan was a dead man.