Naruto: Reincarnated as a Demon King

Outside Konoha...

A crystal-clear river flowed peacefully, reflecting the golden hues of the setting sun. The tranquil scene exuded an air of serenity.

Suddenly!

Splash!

The smooth, mirror-like surface of the river was abruptly broken by a pair of horns!

Looking closer, one would notice a small child with two horns protruding from his head, dog-paddling frantically in the water.

And then… he sank.

Blub, blub, blub...

A stream of bubbles surfaced, and soon the river regained its previous calm.

"Damn it! I almost drowned!"

The horned boy burst out of the water, gasping for breath as he collapsed weakly onto the riverbank.

"I refuse to accept this! I won't believe it!"

"If a dumbass like Naruto can master this, then why the hell can't I?!"

"...or am I also a dumbass?"

Gritting his teeth, Raiden spat out a mouthful of water, dragged himself onto the shore, and focused on channelling the chakra to the soles of his feet.

Then, with a determined gleam in his eyes, he took slow, deliberate steps toward the water's surface.

Yes, Raiden was practising water walking.

SPLASH!

"…Failed again."

Hauling himself back onto the shore, Raiden let out a bitter chuckle, his gaze flickering with an unreadable emotion.

He wasn't originally from this world.

Before arriving in the Naruto universe, he had dreamed of stepping into this world and becoming a genius But dreams were idealistic, and the reality was brutal.

Raiden's body was weak. A classic out-of-shape couch potato covered in fat but with zero real strength.

His chakra reserves were decent, barely above average. But his chakra control?

Absolute garbage.

Tree climbing? Even using both hands and feet, he couldn't do it.

Water walking? Emmm…

"Even after all this training, I've lost weight, but my strength is still bottom-tier."

Raiden clenched his fist, imagining the day he could smash opponents with a single punch.

Poor chakra control meant ninjutsu and genjutsu were practically out of the question for him.

Sure, someone could still become a powerhouse by mastering taijutsu alone, but a fleeting moment of glory wasn't what Raiden wanted.

...

The scars of the Third Shinobi War had yet to fade.

Konoha had just endured its greatest loss in history the Nine-Tails attack. Both the Fourth Hokage, Minato Namikaze, and the Nine-Tails' Jinchūriki, Kushina Uzumaki, had perished.

Half the village was in ruins. The bodies of shinobi and civilians alike could pile up into a small mountain.

With no other choice, the nearly sixty-year-old Third Hokage, Hiruzen Sarutobi, had stepped back into power to hold up a crumbling Konoha.

The village was in a fragile, storm-ridden era.

"Fighting isn't scary, what's terrifying is when your own people start scheming."

Raiden sighed. He was only six years old. Last year, the Nine-Tails incident had occurred.

If history followed its proper course, Konoha would experience a period of relative peace in the coming years. As long as he played it safe, he could survive until the main storyline began.

But… what if things didn't go as expected?

More importantly, Raiden didn't want to just survive. If he couldn't shine in this world, then what was the point of coming to the Naruto universe at all?

"I'll keep training. The day I stop striving to grow stronger is the day I give up on life itself."

Regardless of whether it was ninjutsu, genjutsu, or anything else, everything started with a strong body. Physical strength was the foundation of it all.

Shaking his head to clear his thoughts, Raiden stood up and headed toward the Ninja Academy. Currently, he is in his first year at Konoha's Ninja Academy.

Today wasn't a holiday, yet he had been training alone outside the village.

Why?

There was only one reason he had been abandoned by his teachers. There were two kinds of students a teacher would abandon:

1. Unteachable prodigies, so gifted that traditional lessons weren't necessary.

2. Hopeless failures are those who couldn't learn no matter how much effort was put in.

Raiden, without a doubt, belonged to the second category.

A true, undisputed dead last.

As he stepped into the academy grounds, the students on the training field immediately turned to look at him.

Their eyes were filled with disgust.

"Look! That freak showed up again!"

"So gross! He has horns on his head! Is he some kind of demon?!"

"Why hasn't the village kicked this monster out yet?"

The insults weren't whispered they were spoken loud and clear as if they wanted to make sure Raiden could hear every word. Their contemptuous gazes bore into him as if he were some filthy, repulsive creature.

Raiden simply rolled his eyes.

'You uncultured brats wouldn't know true beauty if it hit you in the face.'

'He was a chibi-style, adorable little kid, damn it!'

'Did they even understand aesthetics?'

He wasn't born with these horns, He had eaten a strange fruit just before enrolling in the academy.

A fruit he recognized immediately.

A Devil Fruit from the world of One Piece.

At first, he had thought he had hit the jackpot gaining a cheat ability to survive in this world.

But in the end?

Aside from growing a pair of horns, absolutely nothing happened.

Well… except for one thing.

Zoan-type Devil Fruits strengthened the physical body. Over time, Raiden's formerly weak and flabby body had undergone a significant transformation thanks to rigorous training.

If nothing else, at least he was tougher now.

Did that count as an ability?

After growing horns, he had gotten used to cold stares and disdain. Even at only six years old, Raiden had already become indifferent to it.

Later, he arrived at the secluded forest behind the academy. Few people came here. It was quiet and isolated, making it the perfect place for training.

He approached a wooden training post, glancing at the deep cracks that had formed on its surface.

His relentless attacks had damaged it beyond repair.

Blood and sweat had soaked into the wood, leaving faint marks as evidence of his perseverance.

Simply put the post was already ruined.

Turning away, he walked toward a large boulder.

Without hesitation, he swung his fist forward.

Boom!

A solid strike landed against the jagged surface.

His Zoan-type Devil Fruit had given him an undeniable boost in endurance and recovery speed.

No ninjutsu talent?

No problem he'd train his fists.

No genjutsu talent?

Screw it he'd keep training his fists.

Would effort guarantee success?

Maybe, maybe not.

But not trying is definitely guaranteed failure.

Give up?

Never.

"One thousand punches. My goal is to shatter this rock."

Raiden stared at his small fists, the disproportionately thick calluses covering his knuckles.

Taking a deep breath, he resumed training.

Bam! Bam!

Pain?

Of course.

But after the pain came numbness.

Sweat poured down his face.

As darkness fell, the academy emptied.

Yet, in the quiet forest, a lone figure kept punching.

At some point, a dark, flame-like aura flickered around his fists…

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