Naruto: Reincarnated with a programmable system core.

Minato's eyes narrowed as well, his mind racing. The chakra emanating from the masked figures was indeed familiar, yet... twisted somehow as if cloaked or altered. But there was no mistaking it—the power belonged to people he knew. However, before he says anything.

"We're under attack!" yelled Anbu; the warning was barely heard before a rain of kunai and jutsu crashed down on Minato's previous position, the ground erupting in an explosion of debris and fire.

In a flash of golden light, Minato reappeared meters away, his kunai clenched tightly in his hand.

The group was surrounded. Uchiha shinobi, with their Sharingan spinning in eerie synchronization, formed a tight ring around them. At their forefront stood two oni-masked individuals—Danzo and Hiruzen.

"Danzo… Hiruzen, its you!" Minato muttered under his breath, his tone a mix of disbelief and mounting fury. "You betrayed us."

Danzo removed his oni mask slowly, revealing his face, "Betrayal? No, Hokage," he said, "This is for the greater good of Konoha. A future without your idealistic weakness."

Hiruzen, still masked, stepped forward, his staff resting against his shoulder. "I warned you, Minato. The path you've chosen will lead Konoha to ruin. Tonight, we correct the course."

Minato gritted his teeth, his resolve hardening. "Then I'll stop you both, here and now!"

The fight erupted with a deafening roar. Jutsu lit up the night like fireworks as Minato, Jiraiya, Tsunade, and the Anbu operatives defended themselves from the combined assault.

Minato darted forward, clashing with Hiruzen in a blur of speed. Hiruzen swung his staff with the precision of a seasoned warrior, blocking Minato's strikes and countering with swift, calculated blows. Fire-style jutsu erupted from Hiruzen's hands, forcing Minato to teleport away in rapid succession.

"You still have much to learn, Minato," Hiruzen said, his voice steady even as his attacks grew fiercer. "Experience outweighs youth."

"You'd know that better than anyone," Minato retorted, hurling a kunai that grazed Hiruzen's cheek before exploding in a burst of smoke.

On the other side of the battlefield, Jiraiya faced Danzo.

The elder's cold, analytical gaze tracked Jiraiya's every move like he was a machine, his genjutsu causing brief distortions in Jiraiya's vision.

Meanwhile, Tsunade fought alongside the Anbu operatives, taking on the bulk of the Uchiha forces. Her chakra-enhanced punches sent shockwaves through the battlefield, scattering shinobi like leaves in a storm.

While the battle raged on, Orochimaru moved through the shadows like a serpent, slithering past the chaos undetected. His destination was clear: the home of Fugaku Uchiha, head of the Uchiha clan.

The guards stationed outside the compound were alert, their Sharingan scanning the surroundings. But Orochimaru's mastery of stealth proved superior. He slipped past them unnoticed,

As he reached the upper levels of the compound, he found his way to Itachi's room.

Orochimaru pushed the door open without hesitation, stepping into the dimly lit space.

"Itachi Uchiha," Orochimaru hissed, his golden eyes narrowing as they fell on the young boy standing in the middle of the room.

His nose caught a faint smell of iron; otherwise, the room was clean.

Itachi turned to face him, his expression calm yet unreadable. In his hands, he held an odachi, the blade gleaming faintly in the moonlight.

Orochimaru's grin widened. "You've grown… exceptional, Itachi. But you'll be even greater with my help."

As Orochimaru took a step closer, he saw Itachi's eye.

The boy's Sharingan spun, but instead of the familiar tomoe pattern, Orochimaru saw something far more intricate. The complex pattern of the Mangekyō Sharingan before his eyes, radiating power, unlike anything he'd seen before.

"What… is this?"

Itachi remained silent, his grip tightening on the sword.

Orochimaru's gaze flickered to the syringe on the desk nearby, realization dawning on him.

This wasn't natural. This wasn't the result of mere talent or lineage.

Somewhere, somehow, someone had elevated Itachi beyond his potential.

However, before he could ask anything, Itachi leaped out of his room, his feet barely making a sound as he landed in the courtyard.

Itachi now has eternal Mangekyō Sharingan.

Yet, his movements were slightly shaky—his body was still adjusting to the brutal transformation that Hiroshi's serum had triggered.

Behind him, Orochimaru slithered into the courtyard.

With a sickening squelch, he shed his skin like a snake, his pale, humanoid form stepping out of his own mouth.

The maniacal grin never left his face as he opened his eyes, revealing crimson Mangekyō Sharingan.

But he wasn't done.

Orochimaru extended his arms, revealing two more Mangekyō Sharingan embedded in the palms of his hands. "Impressive, aren't they?"

"This is the pinnacle of my research, Itachi. Let me show you true power."

Orochimaru activated the first Mangekyō Sharingan on his forehead. A violent pulse of chakra exploded outward, and his figure began to change. His once-human form twisted—his arms elongating and his fingers turning into claw-like appendages.

"Orochimaru…" Itachi said, "You've turned yourself into a monster."

The serpent-like man grinned wider. "A monster? No, Itachi. Let me teach you, how to use those eyes to the fullest!."

Orochimaru charged forward, his elongated claws swiping at Itachi with terrifying speed.

Itachi dodged, and then he countered with a swift slash of his odachi, but Orochimaru twisted unnaturally, avoiding the blade entirely.

With a flick of his wrist, Orochimaru activated another Mangekyō Sharingan—this one on the back of his left hand. His body shifted again, growing larger and more grotesque. Horn-like protrusions jutted out from his head, and his skin darkened.

Each time he activated a new eye, his form became more monstrous. By the time he awakened the fifth Sharingan, Orochimaru was barely recognizable. His lower body is now that of a snake, his movements now a mix of brute force and unsettling agility.

Orochimaru lunged at Itachi with renewed ferocity, his monstrous limbs smashing into the ground and sending debris flying.

Itachi jumped back, as he analyzed Orochimaru's movements.

But the strain of his transformation still lingered.

'I have to end this quickly,' Itachi raised his odachi. 'I'm still unable to use Amaterasu or Tsukuyomi,' he thought; his chakra reserve is still full, but his body need time to adapt to the new power.

Orochimaru activated another Sharingan, this one embedded on the back of his neck. His body twisted further, his spine elongating unnaturally as sharp spines jutted out from his back.

He cackled, his voice now a distorted mix of human and beast. "Do you see, Itachi? This is what true power looks like!"

Itachi gritted his teeth, charging forward. His blade clashed with Orochimaru's claws, the sound of metal on bone echoing through the courtyard.

Sparks flew as they exchanged blows, each strike pushing Itachi closer to his limits.

But Orochimaru wasn't done. One by one, he activated the remaining Mangekyō Sharingan, his body undergoing further horrific transformations.

By the time he activated the tenth and final Sharingan, he had become a towering, monstrous figure—an unholy fusion of man and beast, with glowing red eyes embedded all over his body.

...

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(A/N: I will release bonus chapter according to the power stone received)