Although Shigure wanted to help, there was nothing he could do.
Right now, he couldn't even leave the underground chamber.
The Six-Tails' chakra inside his body had entered the most critical stage of fusion, and his physical body—strengthened though it was—simply could not move.
Tailed Beast chakra surged wildly through every meridian in his body.
In this condition, even the slightest movement could cause disastrous internal backlash.
So Shigure steadied his breathing and focused entirely on assisting the Great Sage with the fusion process.
One tail…
Two…
Three…
Four…
Gradually, steadily, they merged.
Now the fusion of the Five-Tails had begun, and it was clear that this stage would take some time.
Every time a Tailed Beast fused, Shigure felt a tangible surge in power—his Six Paths energy continuously rising.
It was as if the previously scattered fragments of tailed beast chakra were completing a long-awaited reunion, and with each integration, Shigure's strength grew in a way that felt nearly exponential.
Even buried underground, the chakra barrier he erected kept him safe from the chaos above.
The fusion of the Five-Tails completed. The Six-Tails began next.
The process of merging each beast felt like breaking down their origin chakra and reforging it into something new.
And each successful fusion added another tail's worth of power.
At this rate, Shigure half-joked to himself that he might end up with one head and ten tails.
But the fusion continued relentlessly.
Above ground, the battle intensified.
The frenzied Two-Tails and One-Tail were rampaging, shaking apart what remained of Kirigakure, but their main target had become Nagato.
Even in his berserked state, the tailed beasts were instinctually drawn to the greatest threat on the battlefield.
And that threat was him.
Nagato, already furious, met them head-on. Beast or not—anything that attacked him would be crushed.
Their clash was monstrous, even felt deep underground.
And the destruction they caused to the Hidden Mist was immeasurable.
Shigure felt his chest tighten.
If this continued… what would be left of the village he had painstakingly rebuilt as Mizukage?
Great Sage, hurry!
[Great Sage: Fusion progressing at maximum efficiency. Host, please wait.]
If they waited any longer, the entire Mist would crumble.
This was the village he restored with his own hands.
If it was destroyed now… Shigure would certainly lose control.
Hurry up! he demanded.
At that moment, the Great Sage almost seemed to sigh.
Then—
He began fusing Seven-Tails and Eight-Tails simultaneously.
The pain was immediate and indescribable.
Every inch of Shigure's body felt torn apart and reassembled.
His bones were continuously ground down and reforged.
His meridians throbbed violently—sharp agony pounding through his skull.
Ordinary people would have lost consciousness instantly.
Fortunately, though it felt agonizingly slow, the process actually passed quickly.
Then came the final beast.
Nine-Tails.
The strongest of all Tailed Beasts—naturally, its fusion was the slowest.
As the Nine-Tails' chakra merged into him, Shigure felt a new presence forming within his inner world.
A budding form.
Growing.
Changing.
Ten Tails.
Through his inner vision, Shigure saw it clearly: a nascent Ten-Tails, newborn and not yet matured—yet unmistakably real.
And once the Nine-Tails' chakra completely integrated—
Shigure felt it.
A presence unlike anything before.
The Ten-Tails' chakra was utterly different from ordinary Tailed Beast chakra.
Its eruption shook the earth, waves of power crashing outward.
This chakra alone could amplify his Surgical Fruit ability several times over.
Even his Six Paths power skyrocketed.
Shigure inhaled deeply, trembling from the sensation.
"So this… is the transformation after fusing all the Tailed Beasts?"
"—As expected."
[Great Sage: All Kekkei Genkai may be integrated into the Tailed Beasts to further enhance their power. In addition, the Ten Tails can evolve these Kekkei Genkai into stronger forms. Does the host agree?]
Shigure froze.
Accept?
Was the Great Sage telling him to relinquish all his Kekkei Genkai and feed them into the Ten-Tails?
The idea made him pause.
He lowered his gaze, thinking—when suddenly—
[Great Sage: Although relinquishing your Kekkei Genkai will temporarily reduce your personal combat power, the host will still be able to use all Kekkei Genkai when channeling the Ten-Tails' power—enhanced in evolved forms.]
Shigure exhaled slowly.
The Ten-Tails…
It now existed under his dominion.
Now the causal relationship was simple: the Ten-Tails supplied chakra, and Shigure used that chakra to perform ninjutsu—changing its nature into water, fire, earth, lightning, wind, or other elements.
But the Great Sage was suggesting something far more radical.
He wanted Shigure to skip that step entirely.
Instead of converting chakra into elemental nature transformations himself, he should let the Ten-Tails directly produce the finished power, eliminating unnecessary conversion—and in doing so:
increase the raw strength of every technique,
accelerate execution,
and further strengthen the Ten-Tails itself.
It didn't weaken Shigure at all.
Even so, he hesitated.
All his Kekkei Genkai—every bloodline limit except his Surgical Fruit ability and his dōjutsu—would be fused into the Ten-Tails' body.
He could still use them through the Ten-Tails, yes…
But giving them up felt like handing away pieces of himself.
The Surgical Fruit had to stay with him.
Its origin lay in Six Paths power, and only by keeping it could he draw out its true potential.
And his ocular techniques were non-negotiable.
They were an extension of his perception and combat instinct.
Then—
[Great Sage: Once the Kekkei Genkai fusion begins, and the Ten-Tails evolves with these bloodlines, the host will obtain stronger, evolved Kekkei Genkai.]
Shigure exhaled slowly.
So he wouldn't be losing power—
He would be trading it for something greater.
The transformation began again.
At this critical juncture, Shigure had no idea what form this metamorphosis would take…
He could only hope the result would be favorable.
Magnet Release—fusion.
Storm Release—fusion.
Ice Release—fusion.
Wood Release—fusion.
One after another, the Kekkei Genkai were stripped from his body and drawn into the forming Ten-Tails.
Each time a bloodline vanished, Shigure felt a bizarre sensation—the feeling of something being gently pulled out of him…
Yet in its place, an overwhelming surge of chakra poured back in.
He didn't understand the mechanism, but the effect was undeniable:
His chakra was growing wildly, expanding in waves like a storm-tossed ocean.
The pressure bursting from him intensified, so great that even deep underground he could feel the oppressive tremors in the air.
Above him, the entire Hidden Mist Village sensed it too.
A monstrous chakra presence, rapidly climbing with no sign of stopping.
The suffocating pressure rolled over the village like a tidal wave.
Shinobi froze mid-movement.
Veterans stiffened with instinctive fear.
Even the rampaging tailed beasts faltered for a heartbeat.
Everyone turned toward the same direction.
"T-this is… Mizukage-sama's chakra!"
"It's skyrocketing!"
"It's still increasing—what's happening!?"
No one had ever felt chakra of this magnitude from a single human before.
And it continued to grow.