The mountain forest trembled beneath the thunderclap of Kai's unleashed technique.
Electricity twisted across the sky like dragons of plasma. The torrential rain had parted around him in an enormous ring, repelled by the sheer force of the electromagnetic field. Lightning arced over his shoulders, crawling down his arms like living snakes of white-blue fire.
At the center of it all, the railgun shell spun violently, gripped in a dense magnetic funnel of rotating force. A spiral of crimson metal compressed beyond any ordinary material tolerance, the projectile howled in the storm like a banshee waiting to be released.
To Itachi, this wasn't ninjutsu. It was something akin to divine retribution, a power that defied the very laws of chakra.
He had never encountered anything like it.
There was no hand seal. No chakra fluctuation following the Five Element nature transformations. Just raw destructive force, accelerated by invisible laws he couldn't even perceive.
He didn't know what to call it.
But he knew one thing—
He had to survive it.
"Susanoo!"
With a roar in his heart, Itachi activated the third form of the ethereal warrior.
A massive ribcage of orange-red chakra erupted around him. Vertebrae stacked. Arms materialized. Horned Tengu armor surged over the frame, and behind it, a mirror of shifting color and texture hovered into view—the Yata Mirror.
Kisame stood at his side, stunned as the divine guardian materialized.
The Tengu form of Susanoo reached full manifestation in an instant, its clawed hands lifting to defend. Armor shimmered as chakra plates locked into place. The [Yata Mirror] moved forward like a glowing shield, rotating to absorb impact.
Lightning lit up the sky, and for a breathless moment, even the rain paused—
Then Kai fired.
"BOOM—!!"
The electromagnetic railgun ignited.
The red-hot slug detonated out of the rail with a sound like thunder cracking against steel, tearing through the air faster than sound, trailing a helix of molten sparks.
A moment later, it hit.
The battlefield erupted in blinding light.
Shockwaves slammed through the land like an earthquake. The very air screamed under pressure as the force struck Susanoo's mirror. Rain was vaporized instantly. Trees behind the impact zone were shredded and vaporized into mulch.
Then came the aftermath.
A hollow crater formed where once stood a gentle forest path.
All around, water vapor hissed violently, and a pair of massive trenches extended outward behind the target, where the redirected blast had carved through the terrain like giant claws had raked the land.
Kai lowered his arm slowly, body steaming slightly.
"Acceptable output," he murmured. "Still far from full power, but close enough to a Tailed Beast Ball for comparison."
His Rinnegan scanned the ruins. "Needs more compression and less charge time... and chakra efficiency's still garbage."
Indeed, just one blast had consumed nearly all the chakra he had left. Kai hadn't even attempted to mask it—his legs felt a touch unsteady, his breath mildly taxed.
But for now, he was satisfied.
He'd built an artificial cannon from chakra and metal, combined it with space-time pressure, and shaped it with electromagnetism.
Not bad.
Besides, he was still handsome enough to pull it off.
In the smoldering crater, as the smoke cleared, the final result was revealed.
Itachi knelt in the center, coughing violently, blood streaking from his mouth. His entire body trembled from the aftershock.
The Tengu-cloaked Susanoo had cracked down the middle.
Only remnants of the Yata Mirror still hovered in front of him—its form fractured, flickering like it could dissipate at any moment. His Susanoo had blocked the strike, but barely.
Itachi fell forward, catching himself with one hand.
The chakra cost was monumental. His Mangekyō had burned through nearly all its remaining energy, and the backlash was immense. Even breathing hurt.
Behind him, Kisame's face was pale, eyes wide.
It wasn't just the impact.
It was the concept.
That a single shot—just one—could do this much damage, overpowering what was widely considered the most impenetrable defense in the Uchiha clan's history…
"Impossible…" Kisame muttered. "Even the Tailed Beast Ball wouldn't have broken that. Not like this."
He looked at Kai with horror.
That wasn't a shinobi standing there.
That was a mosnter.
Kisame dropped to one knee and reached out to support Itachi.
"Mr. Itachi, can you hear me?"
Itachi nodded faintly, but his skin was pale and cold. His Mangekyō Sharingan flickered, dimming with exhaustion.
Susanoo faded into nothingness.
Kai approached them calmly.
"Your Susanoo is impressive," he said, "and the Yata Mirror... really lives up to the myths."
He wasn't mocking. In fact, there was a glint of appreciation in his voice.
But the acknowledgment brought no comfort.
Kisame shifted Samehada in front of them, preparing for a final confrontation.
"I can still fight," he growled.
He wasn't lying. Even if he died doing it, he'd buy time.
His muscles coiled as he reached for the hilt.
"Samehada! Sync!"
The sword pulsed, responding to Kisame's will.
Scales merged into his flesh. His skin hardened, chakra surged, and fins sprouted from his back. Within seconds, Kisame had entered his fusion form—a monstrous half-shark beast rippling with power.
Rain sizzled as it hit his skin.
"I'll hold him here," Kisame said through gritted teeth. "You get out—"
"No."
Itachi's voice was quiet, but firm.
He sat up slowly, blood still running from his lips, and turned to look Kisame in the eyes.
"We're not fighting anymore."
Kisame froze.
"What are you saying?"
Itachi exhaled.
"I surrender."
Kisame blinked, confused.
"What?"
"I'm done resisting. This fight... can't be won."
He turned his gaze to Kai, who stood motionless, silent, waiting.
Itachi's right eye spun. His vision was blurry now. The Mangekyō's toll was catching up with him. Already, he felt the warning signs—his light was dimming.
To fight further would mean blindness.
To press forward would mean death.
He couldn't afford either.
Because—
Sasuke still needed him.
"I'll give you my left eye," Itachi said quietly. "Let us go."
Kisame's heart nearly stopped.
"No! Don't—!"
But Itachi didn't waver.
He reached into his own eye socket, blood pouring from his eyelid.
He removed the left Mangekyō Sharingan.
The eye that housed the [Tsukuyomi].
The eye that had manipulated time, bent pain, shaped perception itself.
He held it out in trembling fingers.
Kai stepped forward, Rinnegan gleaming.
He didn't hesitate.
With a flick of his palm, a translucent vortex swirled open—[All-Creation Yin Seal], a miniature spatial node designed to store and preserve ocular tissue.
The eye vanished into the chamber with a flicker of light, now suspended in chakra-preserving fluid.
Kai closed the seal and returned his hand to his side.
Neither he nor Itachi said anything more.
There was no need.
The transaction was complete.
The silence that followed was heavier than the thunder before it.
Itachi sat quietly, his hand covering his now-empty eye socket.
Kisame didn't move.
He hadn't agreed to this deal, but he didn't stop it either.
They had lived. That was enough.
For now.
Kai turned away.
He began walking, his coat fluttering behind him.
No words. No threats. No ultimatums.
He didn't even glance back.
For someone who had so thoroughly dismantled them, his exit was quiet.
It wasn't mercy. It was precision.
Kai didn't kill needlessly.
He had acquired what he came for—the left Mangekyō of Uchiha Itachi—and doing more would only muddy the future.
After all, he needed the Uchiha alive.
They had their roles to play.
Let Madara and Izuna handle the punishment, if punishment was even deserved.
Let Sasuke face his brother with the truth.
Let the dominoes fall.
Kai had what he needed now.
The [Tsukuyomi]—a lens of perception manipulation, essential for the hybridization he had in mind.
The next step would be to graft it into the prototype for the Composite Pupil Technique.
A new eye. One that could handle time, gravity, matter, and mind.
And perhaps...
More.
Kisame finally broke the silence.
"...You gave it up," he said quietly.
Itachi nodded.
"For Sasuke."
Kisame was silent for a long time.
Then he exhaled, Samehada pulsing softly at his side.
"You Uchihas... you really go hard for your brothers, don't you?"
Itachi smiled faintly, though his face was pale.
"More than anything."
They stood there for a long moment.
No more rain. Just silence.
Then, Kisame stepped forward, offered his arm, and helped Itachi to his feet.
"We're not dead yet," he muttered. "Come on. Let's get out of here before he changes his mind."
Itachi chuckled.
It hurt.
But it was real.
They began walking—slowly, steadily, side by side.
Leaving the crater behind them.
And from high above, as if from another plane...
Kai watched.
Not in the literal sense. Not with his Rinnegan or his electromagnetic fields.
He simply perceived.
The stolen eye now floated in its crystalline tube, rotating softly as chakra coils danced through the containment fluid.
He raised it to the light.
"Uchiha Itachi," he whispered.
"You've proven yourself."
"You've earned the right... to be judged later."
He stored the tube in a secured slot in his dimensional belt.
One piece down.
The final weapon was forming.
The chakra of Asura and Indra would one day clash again.
But when it did...
Kai would already be waiting.