One Piece: I will become stronger by checking in

On the vast blue sea, an island with several huge windmills stood tall against the horizon. This was Windmill Village.

At the southwestern edge of the island, a teenager lay sprawled on the sandy beach, his bare feet occasionally brushed by the cold, salty water. Slowly, he opened his eyes, greeted by the endless blue sky above.

The faint scent of the ocean filled the air, and Kai Vane blinked in confusion.

"Where… am I?"

He mumbled to himself, trying to piece things together. The last thing he remembered was being hit by a truck in some bizarre accident while trying to score a profit. His mind, still hazy, struggled to make sense of the situation.

But thinking too much only gave him a headache, so he let it go for now. One thing was for sure: he wasn't dead. Not yet, at least.

Kai pushed himself up from the ground, his hands pressing against the sand. As he stood, something felt… off.

He stared down at his feet in disbelief before frantically touching his face.

"W-What the hell… is this?"

The reflection in the shallow seawater wasn't that of a man in his twenties, worn down by life's trials. Instead, he saw a younger version of himself, a sixteen-year-old, full of energy and promise.

Just as Kai was grappling with this sudden de-aging, a voice echoed in his mind.

[Ding!]

[Plot Island detected: Windmill Village! The Plot Island Check-In System has been successfully activated!]

"Wait… what? A system?"

Kai's mind, already spinning with confusion, grew even foggier. He was alive, not dead—right?

Then something clicked.

Windmill Village?

He'd heard of that name before! It wasn't just any random place… No, this was the Windmill Village!

A cold sweat ran down his back as the voice of the system chimed in again.

[You have arrived at Plot Island: Windmill Village. Would you like to check in?]

"Uh… yes?" Kai responded, almost on instinct.

[Check-in successful!]

[Congratulations! You have received…]

[Animal-Type, Mythical Zoan: Renren Fruit, Monkey King Form! (No side effects version)]

[The fruit has been stored in the system space and can be accessed at any time!]

Kai's eyes widened as the realization hit him. He wasn't just on any island—he was in the world of One Piece!

If he hadn't unlocked this system, he would have been terrified. After all, this world wasn't as lighthearted as it seemed in the anime. Vicious pirates roamed the seas, and the Marines weren't always the righteous heroes they appeared to be. And then there were the despicable Celestial Dragons, always looming with their power.

But now, with the system in his hands, things were different. He had a tool that many could only dream of, and he wasn't about to let fear control him.

Kai summoned the fruit into his hand, the golden skin glinting in the sunlight. The Renren Fruit: Monkey King Form. He recognized the legend behind this character—the Monkey King, Sun Wukong, a figure of unimaginable power.

Just the name alone suggested this fruit was a god-tier item!

"Is Nika the Sun God strong?" Kai smirked. "Well, even if you become a god, you'll just be one of the countless soldiers in my way!"

Without hesitation, he took a massive bite from the fruit. Sweet juice exploded on his tongue, much to his surprise.

"Huh? Didn't people say Devil Fruits tasted terrible?"

Maybe the "no side effects" version also removed the awful taste. Either way, it was delicious, so he kept eating, bite after bite. After all, he was starving!

Before long, he had finished the entire fruit. It didn't look big, but it was surprisingly filling.

As soon as he sat back down, a wave of energy surged through his body. It was like nothing he'd ever felt before, reshaping him from within. The transformation lasted about ten minutes, and when it was over, Kai clenched his fists and felt an overwhelming power coursing through him.

He grinned, certain that he could punch through a mountain if he wanted to.

But then his stomach growled loudly, and his grin turned into a sheepish smile.

Despite feeling stronger than ever, he was hungry again.

Looking around, Kai spotted a large fish swimming nearby. A wicked grin spread across his face.

"Well, looks like lunch just arrived."

…

Later, as he sat by a crackling fire, munching on grilled fish, Kai started to plan his next move. He couldn't stay here for long. The system had mentioned "Plot Islands," and that likely meant the islands that appeared in the One Piece storyline.

His goal was clear: check in at all of these islands and grow stronger. But first, he needed to figure out where in the timeline he was.

Opening the system panel, Kai looked at his stats.

[Name: Kai Vane]

[Fruit: Renren Fruit – Monkey King Form (Basic)]

[Abilities: Indestructible Body (Basic)]

[Armament Haki: Unawakened]

[Observation Haki: Unawakened]

[Conqueror's Haki: Unawakened]

It was a simple display, showing the three forms of Haki alongside his current level of mastery with the Renren Fruit. The Indestructible Body was a perk of his Mythical Zoan form, turning his physique into that of the Monkey King.

The indestructible body of the Great Sage was no joke. It was a legendary form, far superior to even the toughest physical bodies in the One Piece world—like Big Mom's iron balloon skin. His new form made him nearly invincible!

Satisfied with his progress, Kai stood up, his hunger temporarily sated. He needed to head toward the center of the island to gather more information.

As he walked, he glanced toward the horizon. He needed to know what timeline he had landed in, and once he did, he could plan his next move.

And most importantly…

He needed to find a ship.

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Tl note / what do you think renren could be ?