Chapter 1: Return 1
"Naruto Uzumaki! Sasuke Uchiha! I applaud your relentless approach of bravery but that useless bravado will end today!" Isshiki looked at the two with massive arrogance.
"You may think that it is what it is, but I am sure that someone in the future will appear to destroy you wicked," Naruto whilst being choked to death and cannot fight back due to his regressed power, smiled as blood flowed from his ruptured organs and lips.
The two, Naruto and Sasuke, went limp as Isshiki exerted more strength, completely powerless as the strongest source of their strength has vanished.
Naruto's partner, Kurama disappeared due to Baryon Mode, disintegrating the very bits of its chakra.
Sasuke's Rinnegan was stabbed and thus was destroyed.
( I just assumed that in this battle, and not in the scene of possessed Boruto, Sasuke was blinded by Isshiki and not Borushiki)
Naruto and Sasuke aggressively twisted their necks, trying to face each other.
With a glint of the eye, the two ignited their chakras, manifesting orange and violet chakras.
Silently, a sun-moon pattern appeared in one of their hands respectively, grasping Isshiki by surprise.
What was the former arrogance in Isshiki's face was replaced with a terrified expression.
Different in the past, Naruto and Sasuke were able to seal Kaguya using the same jutsu due to the chakra Hagoromo gave them respectively.
Exhausting that special Six Paths Chakra, they reignited its remnants by sacrificing their own chakra onto the waning ember of Six Paths power, thereby reactivating it…at the cost of their own chakras permanently.
Chakras are representations of one's life force and spiritual energy, corresponding to the body and soul.
Depleting will result in one thing…death.
Truth Seeking Balls appeared around Naruto and Sasuke's remaining eye, his Eternal Mangekyo Sharingan, transformed into a complete Rinne-Sharingan.
The force from their sacrificial awakening blasted out Isshiki.
"Naruto, want to compete who can beat that one up faster?" Sasuke provokingly said.
"HAHA, this was the last competition we will have, I'm gonna win Sasuke!" Naruto laughed heartily.
The expression of those two irked Isshiki, flaring his temper up.
"HAHA, by reinforcing that cursed remnants within you, do you think that you can still live after this? How laughable!" As he shouted, Isshiki manipulated the objects around them with pebbles transforming into gigantic pillars.
Kicking it effortlessly, Naruto and Sasuke performed a cooperation jutsu.
"Indras Arrow!"
"Ultra Big Ball Rasenshuriken!"
"Scorch Release: Halo Hurricane Jet Black Arrow Style Zero!"
Releasing their greatest arsenals, Isshiki manipulated the space around them to become narrow, shrinking the Cooperation Jutsu they release to nothingness.
Seeing that Isshiki flatly dispersed their attack, Sasuke and Naruto for another volley of attacks.
Naruto transmogrified his Six Paths Chakra to manifest a Kurama-like avatar with multiple arms.
Sasuke with his Rinne-Sharingan summoned a Susanoo much bigger than what he can do in the past.
Performing jutsus with their life on stake, it was to be expected that the powers behind it are gonna be incredible.
"Sasuke, please guard me for some time, I'm gonna do something," Naruto sat cross-legged and meditated.
Seeing this Sasuke has a guess to what he was trying to do and focused to fend off Isshiki by himself.
Naruto focused his mind and was summoned to a mysterious place where gigantic beings dwell.
"Shukaku, Matatabi, Isobu, Son Goku, Kokuo, Saiken, Chomei, Gyuki, I need your help, could you give me some of your chakras?" Naruto pleaded.
"The hero is back! It is just some chakra, don't be shy with us!" Son Goku said as he teased.
The others nodded, expressing their desire to help.
"What happened to Kurama, we could feel that his presence has disappeared, what actually happened?" Matatabi slowly said.
"As you can feel, Kurama…is gone," Naruto's face was filled with sadness but an incredible determination is still present.
The group became quiet for a while then Gyuki broke the deafening silence.
"This is parts of our own chakras, take this, we wish that this could help you," Gyuki and the others moved their tails, infusing amounts of chakras into Naruto.
On the outside, Naruto's chakra robes tinted with orange pigment were mixed with various of colors representing the chakras the Tailed Beasts gave.
Performing another set of handseals, Naruto summoned gigantic toads with a summoning technique.
"Gamabunta, Gamahiro, Gamaken, Gamakichi! Please help me gather Natural Energy quickly, the opponent we have isn't something I can handle without the help of you, it was now worse that Kurama isn't here so I have to find any alternatives to use" Naruto quickly explained and the Myoboku frogs also followed suit.
With four frogs rapidly accumulating Natural Energy, the four of them fused with Naruto, bringing him large amounts of Natural Chakra.
His face was being distorted from time to time to features akin to a frog but Naruto was able to bear the risk and was able to harmonize the two opposing chakra sources: the Six Paths Chakra and Natural Chakra.
Accumulating power in the multiple arms his Asura Kurama Avatar has, ten types of Rasenshuriken were unleashed.
Sage Style: Tailed Beast Ball Big Bang Rasenshuriken!
Sage Style: Magnet Sand Rasenshuriken!
Sage Style: Calamitic Flame Rasenshuriken!
Sage Style: Spatial Water Rasenshuriken!
Sage Style: Flowing Lava Rasenshuriken!
Sage Style: Boiling Sky Rasenshuriken!
Sage Style: Corrosive Acid Rasenshuriken!
Sage Style: Scale Poison Rasenshuriken!
Sage Style: Creation Ink Rasenshuriken!
Sage Style: Ultra Big Ball Rasenshuriken!
The Rasenshurikens assaulted each other which bewildered both Sasuke and Isshiki but soon dilated their eyes widely, comprehending what Naruto could be planning.
Bearing the impact of the fusions of ten different wavelengths of chakra, Naruto's body bled profusely, withstanding the collisions with pure physical prowess.
"Sage Style: Final Rasenshuriken!"
A gigantic black ball of chakra composed of amalgamated attributes was launched toward Isshiki.
Looking at the ball that made him sense an impending danger, Isshiki tried to shrink it like any other attack but was unsuccessful due to the amount of chakra the massive ball was incorporated.
The space that he tried to manipulate was blasted open with unadulterated force from the unique Rasenshuriken, freely going towards Isshiki with extreme speed.