Naruto: Swarm System

Land of Fire.

In an abandoned underground Uchiha clan stronghold.

Uchiha Itachi sat quietly on a chair, patiently waiting for Sasuke's arrival. His body was already ravaged by illness, beyond any hope of recovery. Before his death, his only wish was to use himself as a tool to awaken Sasuke's Mangekyō Sharingan.

Bang!

The door to the underground room was kicked open, and Sasuke, with a katana at his waist, walked in. Upon seeing Itachi sitting calmly on the opposite chair, Sasuke's eyes instantly turned crimson, with the three-tomoe Sharingan appearing.

Itachi looked at Sasuke with a blank expression and said indifferently, "Sasuke, you are still as foolish and impulsive as ever. You didn't even realize that the information about my location was deliberately spread by me, yet you came alone."

"Utterly foolish."

Sasuke sneered, slowly drawing the katana at his waist, and said, "My current strength has long surpassed yours. I have already learned everything about the Mangekyō Sharingan from my mentor."

Mother, huh...

Itachi instantly guessed who Sasuke referred to as his mentor, causing an inexplicable pang of bitterness in his heart.

Drawing his katana, Sasuke demanded angrily, "Itachi, why did you massacre the Uchiha clan? Why!!?"

The massacre of the Uchiha clan by Itachi had always been a tormenting mystery for Sasuke. He could never understand why Itachi had done it.

"It was merely to test my capacity."

"Capacity?" Sasuke's anger flared instantly.

He couldn't believe that Itachi would slaughter their entire clan just to test something as abstract as his capacity.

Itachi, sitting on the chair with his fingers interlocked, spoke calmly, "It's said that to awaken the Mangekyō Sharingan, an Uchiha must kill their closest kin."

"I awakened the Mangekyō Sharingan after Shisui's death, gaining power beyond the Kage level."

"However, with the frequent use of the Mangekyō Sharingan, my eyesight deteriorated. Eventually, through my research, I learned of the existence of the Eternal Mangekyō Sharingan."

"Eternal Mangekyō?" Sasuke frowned deeply.

Why hadn't his mentor mentioned this?

Itachi continued, "To obtain the Eternal Mangekyō, one needs two pairs of Mangekyō Sharingan that share the same bloodline."

"And to make you awaken the Mangekyō, I chose to massacre the Uchiha clan to stimulate you. Unfortunately, as foolish as you are..."

"Shut up!" Sasuke roared, cutting him off. Hearing that Itachi had slaughtered their clan to obtain the Eternal Mangekyō made Sasuke explode with rage.

In the next moment, Sasuke saw Itachi appear before him, reaching for his eyes.

"Release!"

Sasuke's three-tomoe Sharingan spun, breaking the genjutsu instantly.

Freed from the genjutsu, Sasuke quickly took out shuriken from his storage seal, attacking the still-sitting Itachi.

Itachi responded in kind, engaging in a shuriken battle.

Clang, clang, clang!!!

The sound of shuriken clashing echoed densely in the underground room.

Zap!

Squelch!

Suddenly, the sound of electricity crackled amidst the clashing shuriken.

A katana infused with lightning pierced through Itachi's back, emerging from his chest.

"A shadow clone..."

Seeing the dissipating clone behind him, Itachi realized what had happened.

Sasuke had cleverly used a transformed shadow clone among the shuriken to stage a surprise attack.

Squawk!

With the sound of crows, the injured Itachi turned into a murder of crows and reappeared nearby.

"Looks like you've grown a lot," Itachi remarked with a hint of pride.

Sasuke, with a cold expression, demanded, "Who else helped you massacre the Uchiha clan?"

Even with the Mangekyō Sharingan, Itachi couldn't have single-handedly wiped out the entire Uchiha clan. There must have been another collaborator.

Itachi shook his head, refusing, "You are already as good as dead; there's no need to know."

Uchiha Obito's abilities were too bizarre. Itachi didn't want Sasuke to get involved. It was better to leave Obito to the user of the Flying Thunder God technique.

Sasuke's face turned cold as he quickly formed hand seals.

Fire Release: Great Fireball Technique!

A massive explosion rang out as the battle between Itachi and Sasuke resumed, bursting from the underground room to the surface.

Outside the stronghold.

Uchiha Mikoto watched the deadly battle between Itachi and Sasuke with tears streaming down her face, heartbroken.

Shishou stood beside Mikoto, gently comforting her.

He hadn't wanted Mikoto to witness the battle between her sons, but she insisted on coming.

In Shishou's eyes, death was the best ending for Itachi. And before his death, if he could help awaken Sasuke's Mangekyō Sharingan, it would be ideal.

As the battle between Sasuke and Itachi continued, they fiercely clashed with shuriken, genjutsu, ninjutsu, and taijutsu, proving to be evenly matched.

Although Sasuke lacked Orochimaru's power as in the original story, he had Itachi's jutsu information and Uchiha Mikoto's strength.

As a result, he managed to fight Itachi to a standstill for a while.

Through meticulous planning and the use of his powerful Kirin technique, Sasuke forced Itachi to bring out his Susanoo.

Seeing this, Sasuke's three-tomoe Sharingan spun rapidly, summoning his own Susanoo around his body.

This was possible because Uchiha Mikoto had used a transfer seal to implant the power of Susanoo into Sasuke's eyes, allowing him to summon Susanoo in critical moments.

This was why Sasuke had been so eager to find Itachi and seek revenge.

"This is... mother's Susanoo..." Itachi was slightly surprised but quickly engaged Sasuke.

The clash of their Susanoo devastated the surrounding landscape, filling the air with deafening roars.

As time passed, Sasuke's Susanoo was the first to dissipate, revealing his exhausted form.

Soon after, Itachi's Susanoo also collapsed.

Seeing Itachi approaching him, Sasuke panicked. He had exhausted all his trump cards and chakra, leaving him defenseless.

Reaching the cornered Sasuke, Itachi coughed up blood. Using Susanoo had worsened his condition.

Seeing Itachi stretch his hand toward him, Sasuke trembled.

However, Itachi merely poked his forehead.

"Sasuke, forgive me, one last time."

_____________________

POWER STONE!!!!

__________________

This fanfiction is complete on my P@treon. If you want to read it, you can find it at [email protected]/Betek.

_____________________