Kushina hadn't just miraculously learned the Multiple Shadow Clone Jutsu after being revived through the Edo Tensei and following the Second Hokage around in the Hidden Rain.
She had already completely mastered the technique while she was still alive.
In the original timeline, Tsunade herself had once remarked, "Naruto is just like Kushina in both personality and ninjutsu."
Now, if she had been talking about someone like Hiruzen Sarutobi or Kakashi, who knew countless, complex techniques, that statement wouldn't necessarily let you infer much.
But Naruto? One Shadow Clone, one Rasengan.
What else did he even have? Oh, right—that infamous, highly censored Transformation Jutsu variant!
Surely Tsunade didn't mean that Kushina used that too, right?
Regardless, as a pure-blooded member of the Uzumaki Clan, Kushina possessed enormous chakra reserves.
The number of Shadow Clones she could casually produce was no less than Naruto's.
Meanwhile, Naruto had already spent an entire grueling day masturbating in the desert and was practically running on fumes, so the number of clones on his side was clearly dwarfed by Kushina's army.
"You rotten, evil woman! You actually copied my Multiple Shadow Clone Jutsu!"
Realizing he had fallen into a massive numerical disadvantage, Naruto quickly started scrambling for a countermeasure.
(Tobirama: Say that again? Whose technique is it?!)
"I'm such an idiot!" Naruto suddenly thought of something, smacked his own forehead and cursed his tunnel vision.
He had been so hyper-focused on developing the Rasenshuriken and mastering the Tailed Beast Bomb—and so deeply frustrated by the fact that he hadn't mastered them yet—that he had completely overlooked one basic fact: he could still use the ordinary Rasengan whenever he wanted!
Why had he been fighting with his bare fists this whole time?!
"RASENGAN!"
One of Naruto's golden clones, aided by two others, formed the swirling blue sphere and violently smashed one of Kushina's clones into dust.
Right after that, having regained his familiar combat rhythm, Naruto's army began a massive counterattack.
Large numbers of his Shadow Clones started manifesting Rasengans.
"Rasengan, huh? ...RASENGAN!"
When Kushina saw the glowing Naruto in front of her form the jutsu, she glanced down at her own right hand, smiled fiercely and instantly formed her own swirling blue sphere to meet his head-on.
At the exact same time, Kushina's entire army of Shadow Clones also began charging Rasengans.
It was as if Naruto had just foolishly broken the unspoken rule of "not using ninjutsu," escalating the brawl into a war!
Of course Kushina knew the Rasengan.
In shinobi history, it was a well-documented fact that Minato Namikaze developed the Rasengan specifically because its chakra-shaping principles perfectly suited Kushina's massive chakra reserves.
At the same time, the Rasengan had been directly inspired by the Tailed Beast Bomb.
Mastering and developing the Rasengan was basically a stepping stone to help a Jinchūriki gradually learn to fire a true Tailed Beast Bomb.
"HUH?! She even copied my Rasengan too?! Could this evil woman be some kind of Copy Ninja like Kakashi-sensei?!"
When Naruto saw Kushina effortlessly wield his signature move, his face became a hilarious mix of shock, frustration, and deep grievance.
It was exactly like Dio realizing Jotaro had entered the cheat code of "Looks like we have the same type of Stand," and then casually gaining time-stop!
"What do I do, Kurama?!" Out of options, Naruto desperately begged the giant fox for help.
His opponent had the exact same golden Nine-Tails Chakra Mode, the exact same Multiple Shadow Clone Jutsu, and somehow knew the Rasengan.
She even had one more overpowered trick than he did: the Adamantine Sealing Chains.
And on top of all that, she possessed an immortal Edo Tensei body with infinite chakra and infinite regeneration!
This was basically like fighting a hacked, premium version of himself with unlimited resources!
How the hell was he supposed to win?!
[...]
"Kurama, say something! Don't tell me you want to take over my body to fire a Tailed Beast Bomb?!"
Seeing the fox remain silent, Naruto nervously proposed an idea.
Even if a Jinchūriki hadn't mastered the Tailed Beast Bomb themselves, they could still cheat by letting the Tailed Beast temporarily take the wheel.
That was the primary reason the various hidden villages could deploy them as weapons of mass destruction.
A Tailed Beast could just fire the bomb on its own.
A Jinchūriki mastering the move was more of an "extra skill" developed much later.
[No. Even if I took over and fired a Tailed Beast Bomb, wouldn't the other side just fire one right back? Naruto, you need to think of something that ONLY YOU can do if you want to defeat her!] Kurama rejected Naruto's proposal without a second thought.
The reason Kurama gave was perfectly sound.
Indeed, although Kushina also hadn't formally mastered the Tailed Beast Bomb, she could still execute the exact same cheat code Naruto proposed—hand her body over to the Yin Nine-Tails and let it fire one.
[Besides, don't forget she has an Edo Tensei body. Even if our Tailed Beast Bomb successfully blew her to pieces, the ash would just recover in no time.] Kurama added one more brutal truth to ensure Naruto abandoned that line of thinking entirely.
"Right… Impure World Reincarnation." Naruto's face fell.
He entered deep thought, pacing inside his mindscape.
He suddenly recalled the cryptic hint Kurama had given him earlier.
'Physical damage is useless.'
'What you need is MENTAL damage.'
He had already used the Reverse Harem Jutsu. Was he supposed to use it again? No.
He actually still had one more highly classified technique that came with catastrophic mental damage attached!
This move had originally been a weapon he planned to combo with Sasuke's Fire Release.
He didn't expect to bring it out so soon!
"Kurama, I'm going to undo the seal." Naruto reached a hand toward his own stomach.
Ever since he had fully reconciled with the Nine-Tails, the beast no longer lived trapped behind the iron cage.
Naturally, the Eight Trigrams Seal was no longer necessary to hold him.
But Naruto, being remarkably clever, had decided to "recycle waste" by using the empty seal space to store the excess toad oil produced in his gut after eating the highly oily foods from Mount Myōboku.
That's right—the exact same volatile gastric substance Naruto had once tragically mistaken for gas, resulting in him having to wash his pants by the river in shame.
...
"What is that kid trying to do now? Hasn't he already reconciled with the Nine-Tails? Why is he still messing with the Eight Trigrams Seal?" Kushina's real body, watching Naruto's glowing form from a distance, tilted her head in genuine puzzlement.
Down in the sand, Naruto's real body called over a Shadow Clone.
The clone hoisted Naruto onto its shoulder like some kind of heavy artillery cannon, aimed his asshole directly at the battlefield—
—and Naruto shouted at the top of his lungs:
"TAKE THIS! TOAD OIL SPRAY!!!"
The Shadow Clone violently yanked aside Naruto's pants, releasing the physical obstruction and a filthy, highly pressurized torrent of slick oil erupted out across the dunes!
Kushina's eyes widened in sheer, unadulterated horror.
She frantically formed a hand seal and desperately canceled her own Shadow Clones.
On the battlefield, Kushina's clones began disappearing one after another with rapid poof! poof! poof! sounds.
She had absolutely no desire to receive, from a hundred different angles, the traumatic sensory feedback of being drenched in that!
Some of the clones didn't even have time to dispel themselves, wildly fleeing and dodging the blast radius while vanishing.
Amidst the chaotic rout, one specific Shadow Clone ran right up beside Kushina.
Kushina didn't even notice it in her panic.
Suddenly, that "clone" transformed back into Naruto, thrusting forward with a massive Rasengan already spinning in his hand!
This time, Naruto had deliberately not mixed a single drop of malice into the attack.
After repeatedly thinking it through, Naruto had given up on the idea of ripping Kurama's chakra back, and he clearly understood that a Rasengan could not inflict any real lasting damage on an Edo Tensei body.
Therefore, there was absolutely zero hostile intent or killing intent in the strike, rendering Kushina's malice-sensing completely blind to the feint!
"SUPER GREAT BALL RASENGAN!"
The massive Rasengan attacking Kushina was heavily reinforced by Naruto's real body, who had rushed over while awkwardly holding up his pants with one hand.
With one final slap of chakra, the sphere violently expanded into a gigantic, roaring Super Great Ball Rasengan.
Even though the tactical setup had been incredibly indecent and disgusting, this whole string of brilliant feints made Kushina feel a deep, overwhelming sense of maternal pride in Naruto's battle instincts.
Smiling softly, she simply chose not to defend herself with the Nine-Tails chakra anymore.
Without the dense protective armor of the golden chakra cloak, an Edo Tensei body was as physically fragile as paper and she instantly shattered into a cloud of flying ash!