Raphael's Invocation
Sukunahikona
While Mirror Itachi was rapidly healing his wounds, the black hole suddenly disappeared. Instead, flying above the water, Isshiki, in his complete resurrection form, appeared with his eight-spoked golden eye.
"Can your Mirror Clone keep up with your strength even now?" Seeing Itachi's Mirror Clone, Isshiki spoke calmly, though Itachi could still hear the astonishment in his voice.
Indeed, his Mirror Clone Jutsu could be said to be one of the most overpowered jutsu in the Naruto verse. Although the conditions for creating a successful Mirror Clone were a hundred times stricter than before, doubling a Six Paths-level fighter was still heaven-defying.
"Indeed, so Isshiki, wash your neck."
The Mirror Clone, who had completely healed, spoke with a smile.
"Damn Uchiha."
Hearing the contemptuous tone, Isshiki became angered.
Sukunahikona
With a wave of his hand, Isshiki summoned tens of thousands of black rods and then threw them all over the ocean with immense force.
Golden Lightning Style: Golden Awakening
"Isshiki, you are the winner of the first round of Taijutsu. Let's start the second round."
Both Itachis, seeing the rain of black rods, summoned Golden Lightning and used it to enhance their bodies.
Even Itachi was impressed by Isshiki's Taijutsu, which was the highest level he had ever seen. Even under a thousandfold gravity, Isshiki was able to overpower him, making Itachi want to defeat Isshiki in Taijutsu.
PIERCEE × n
The next moment, both Itachi rushed towards Isshiki while dodging all the black rods with their enhanced reflexes and senses. Within a few seconds, both Itachi reached Isshiki as they punched him from both sides.
Isshiki, facing this, blocked the two fists with his own hands and then redirected the force back at the two Itachi. However, Isshiki's hands were also scorched by the Golden Lightning.
' I can't absorb that golden lightning ? '
The two Itachi, who had been pushed off balance, quickly regained control. Mirror Itachi teleported next to Isshiki while slashing towards him with his claw, while main Itachi, on the other hand, bolted straight towards Isshiki, aiming his fist at his stomach.
The next millisecond, Isshiki had already neutralized Mirror Itachi's attack while blocking Itachi.
For the next few minutes, Isshiki fought Taijutsu with both Itachi to a standstill until they finally found their chance.
When Isshiki was distracted by the hundred of shadow clone, both the original and the Mirror Clone punched Isshiki from two directions, covering every possible escape.
Sukunahikona
Isshiki dodged the blows by shrinking himself to microscopic size. However, Itachi had prepared for this move.
Six Paths Fire Style: White Death
The next moment, a wave of white fire expanded from the main body, covering thousands of meters. Isshiki, who was microscopic within this range, also felt the burning pain on his body as he used the Preta Path's power to absorb the white flames.
'Found you.'
Second Style: Event Horizon
Sensing Isshiki's location, Mirror Itachi thrust his burning spear towards him.
Teleport
Feeling the threat, Isshiki teleported outside the fire domain. Mirror Itachi passed Sagittarius to Itachi as he rushed towards Isshiki like a golden lightning.
Itachi, holding Sagittarius, changed its shape into a purple-black bow. Stretching the string, a spear-shaped arrow formed upon it. Taking aim, Itachi fired the arrow at Isshiki, who was fighting Mirror Itachi.
BOOMMMM
Isshiki teleported hundreds of meters away before the arrow could hit him, as the arrow struck his previous location and immediately expanded into a sphere the height of a twenty-story building, absorbing the surrounding water.
Scale of Sagittarius
Itachi repeated the process, sneak attacking Isshiki whenever he was about to overpower the clone. Every time, however, Isshiki escaped with teleportation.
Scale of Sagittarius
Itachi repeated the attack for the fifteenth time. This time, however, when Isshiki tried to teleport, he couldn't.
Sukunahikona
Isshiki, dodging the Mirror Clone's claw, used Sukunahikona on the arrow, but he couldn't shrink it. Shrinking himself was also useless, as he would still remain within its range.
Daikokuten
Sensing the impending doom, Isshiki expanded multiple black cubes into the arrow's path.
BOOMMMMMMM
The arrow and the giant cubes collided, and for the first time, the black cubes were shattered before being sucked into the arrow. However, they bought enough time for Isshiki to escape.
Daikokuten
After escaping, Isshiki looked around him at the fifteen faint spheres arranged randomly across the battlefield.
'A sealing jutsu... restricting my Space-Time Jutsu.'
With a wave of his hand, fifteen huge cubes fell from the sky, targeting each sphere.
Six Paths Sealing Jutsu: Planetary Devastation
Just then, Mirror Itachi threw a small black sphere towards Isshiki. The next millisecond, all the black cubes that were about to collide with the huge spheres stopped and instead rushed towards Isshiki at bullet speed.
Sukunahikona
Eighth Style: Orbit of Death
While Isshiki was busy dealing with Planetary Devastation, Itachi threw Sagittarius towards him. This time, however, instead of hitting him, Sagittarius bent through space and started orbiting around Isshiki. With each rotation, the gravity within that space increased.
Isshiki, seeing this, tried to leave the area, but Mirror Itachi punched him back inside with his Golden Lightning Fang Fist.
Ten Seconds — 100×g
Thirty Seconds — 1,000×g
One Minute — 10,000×g
Three Minutes Later
After a full three minutes, the gravity inside the space became so overwhelming that Isshiki couldn't even move. Although he tried to use black rods and giant cubes to destroy the sphere ( domain where Isshiki is trapped ) from the inside and outside, all his attacks were pulled away by Planetary Devastation while Mirror Itachi blocked every possible escape.
Ninth Style: Singularity Collapse
Finally, when Isshiki felt that he would explode due to the immense gravity, Sagittarius stopped revolving and pierced him from behind.
Freed from the gravity, Isshiki used Sukunahikona to get rid of Sagittarius as he examined the hole in his chest. As for why he hadn't used Sukunahikona earlier to escape, if he had, he would simply have become an easy target for Mirror Itachi. In his microscopic form, he wouldn't have had his normal Taijutsu, while Itachi could have simply spammed Golden Lightning inside the sphere until the gravity became unbearable.
"Isshiki, I specially created twelve Styles of Sagittarius to counter you, but it seems I won't need the remaining three moves. Before we end this fight, I have a few questions."
Itachi looked at the panting Isshiki and spoke calmly.
"Ask."
Isshiki replied while trying to heal his wounds. Originally, he had only three days left to live after Jigen's body was destroyed, but with this intense fight, his body was deteriorating faster and faster. Now, he had only a few hours left, and even those were rapidly disappearing as he healed himself.
"In the past thousand years, you were always hiding. Why did you suddenly become active and start monitoring Mizumori?"
"The Ninja World was getting out of my control. With you acting as its protector and your abnormal rate of growth, I had to leave my seclusion. Then, with the help of your blood, I discovered that you possessed the most perfect body for my resurrection, so I waited for the perfect opportunity to strike.
Seeing Urashiki's arrival, I wanted to capture your body quickly without damaging Jigen's body too much, but it seems you had known my plan all along."
"Thanks for clearing up my doubt... then, goodbye."
COLLAPSE
With a single thought from Itachi, the tiny singularity he had planted inside Isshiki's body during the previous attack collapsed inward. Within the next millisecond, Isshiki's body began being sucked into itself. If Isshiki used Sukunahikona, he would die even faster, leaving him with no path to survival.
"Damn bastard... your body will eventually be mine!!!"
Feeling his inevitable death, Isshiki cursed Itachi as he used the last of his power to try to pass his Karma Mark onto Itachi.
The next moment, he was absorbed by the singularity as it collapsed into nothingness.
Itachi, on the other hand, could see Isshiki's spiritual will rushing towards him while Isshiki was being annihilated by the singularity. He could have teleported away to avoid Isshiki's spirit, but ultimately, Itachi didn't move.
The next second, Isshiki's spiritual will entered Itachi and placed a black Karma upon him while a diamond-shaped pattern appeared on Itachi's forehead.
Looking at the empty space before him and feeling the ability to exit LIFE-DEATH ARENA return, Itachi understood that Isshiki was truly dead... unless he revived through the black Karma.
As for why he didn't dodge Isshiki's spiritual will... well, he wanted Isshiki's Kokugan and Otsutsuki body. Since his strength had reached Six Paths level, he had been planning to obtain Isshiki's eyes. That was also the reason he hadn't awakened the Rinnegan with the help of the Sage of Six Paths.
As for the possibility that Isshiki would take over his body after he reached 100% Otsutsukification... well, he had numerous countermeasures, such as his EX-Level Fūinjutsu to seal Isshiki's spiritual data or other Fūinjutsu to protect his soul from foreign interference.
He also had Domain Expansion, which could control all forms of energy, including Isshiki's spiritual energy inside his body. If that didn't work, then there was Yggdrasil, currently residing in his spiritual space to guard against Isshiki. That was also the reason he hadn't used Yggdrasil throughout the fight.
Finally, if all else failed, he could only go to the Sage of Six Paths or wait for a System reward.
As for why he didn't simply let Isshiki place the Karma Mark on him directly if they ultimately had the same goal... well, Isshiki was still a thousand-year-old alien. Who could guarantee that he wouldn't leave behind other hidden countermeasures inside his body, just as Madara had done to Obito?
And, after all, a dead Otsutsuki is a good Otsutsuki.
He could have also taken physical kokugan and transplanted it like Nagato but, that's imperfect and he didn't even know whether he could access the Dojutsu that way. Even if he could, he didn't want to loose his Mangekyo Sharingan....that would be loosing a watermelon over a sesame seed.
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Author's Note
Hello everyone!
So, the fight between Isshiki and Itachi ends with Itachi finally receiving his own tattoo.
I've actually wanted to give Itachi the Kokugan for a long time. One reason is that the Rinnegan has become far too common in Naruto fanfiction. In four out of three fanfics, the protagonist somehow ends up with a Rinnegan. I wanted to do something different.
Lately, I've really come to like Isshiki's Kokugan and its Sukunahikona ability. The power to shrink attacks and objects, then restore them to their original size, doesn't necessarily give Itachi a massive increase in raw power, but it changes his fighting style and tactics.
The second reason I didn't give him the Rinnegan is that, at Six Paths level, Itachi can already perform almost everything the Rinnegan offers. The only unique advantage is its dōjutsu abilities, and the Kokugan fills that role perfectly. With 100% Ōtsutsukification, Itachi's physical abilities would also increase tremendously, especially his taijutsu, which has always been one of his weaker areas.
After finishing the fight, I also realized that I could have ended it much more easily. For example, I could have simply erased Isshiki's black chakra rods and giant cubes using Domain Expansion instead of dealing with them directly. On top of that, I had four Six Paths-level fighters available—Yggdrasil, Sagittarius, the Mirror Clone, and Itachi himself. I also barely used many of Itachi's strongest abilities, such as his Mangekyō Sharingan Tariff and Sanction, and several other trump cards.
Writing this battle really made me realize just how powerful Itachi has become, at least in the context of my story.
Anyway, the next chapter will focus on Itachi receiving his power-up, even if he doesn't really need it anymore. After that, the fight with Urashiki will finally come to an end.
Once that arc is over, I think it's time for a new world. Right now, the arc I'm leaning toward the most is One Punch Man.
See you all in the next chapter!