Here is a bit of trivia:
The Seven Ninja Swordsmen of the Mist are not a monolithic group. In fact, every member harbors nearly irreconcilable conflicts with the others.
This stems from the fact that the seven wielders belong to entirely different departments.
Fuguki Suikazan belonged to the Kirigakure Hunter-nin Force. Kushimaru Kuriarare and Jūzō Biwa were part of the Anbu under the direct command of the Mizukage. Jinpachi Munashi and Jinin Akebino belonged to the Surprise Attack Division. Raiga Kurosuki, on the other hand, was a member of a squad that executed high-difficulty missions specifically for the Mizukage, likely falling under the jurisdiction of the Jōnin Commander.
The mysterious Third Mizukage maintained a precise and delicate balance between the Seven Ninja Swordsmen, ensuring these desperate outlaws remained tools for his use.
However, Kushimaru Kuriarare and Jinpachi Munashi—two individuals with completely different personalities and terrible compatibility—were able to cross departmental lines and form the "Heartless Duo" for one reason only:
The Blastsword: Shibuki and the Longsword: Nuibari formed a perfect synergy.
The strength of both swords lay in their extreme lethality; a single hit usually meant death or permanent disability. Their weakness, however, was that in a direct confrontation where their abilities were known, it was difficult to actually trap an enemy. The Longsword: Nuibari required the pre-placement of wire threads, while the Blastsword: Shibuki's attack patterns were straightforward and easily predicted.
But once you combined Kushimaru's speed—which was currently no less than that of the Third Gate-active Hyuga Yu—with Jinpachi's strength and area-of-effect damage, the situation spiraled downward. As the two wielders coordinated their feints to create openings for one another, the battle became a nightmare.
Just like now—
After opening the Third Gate, Hyuga Yu had relied on his taijutsu and information advantage to quickly defeat Ao. But against these two?
In just two exchanges, one of his arms had been blasted and one of his eyes blinded.
Even so, Yu's expression remained unchanged. Once he had identified the specific names of his enemies, these developments fell within his range of predictions.
His mission was to bring back the Main Branch's Byakugan. His goal was to rescue Hyuga Natsu and Hyuga Tetsu.
In that regard, Yu had already accomplished two-thirds of what he set out to do.
What came next was to give these two individuals a memory they would never forget—and to buy enough time for Hyuga Natsu to escape the battlefield.
At this moment, at the cost of one Byakugan, Hyuga Yu kicked off the air mid-flight to flip backward, escaping the range of Kushimaru's Longsword Ninja Art: Earth Spider Stitch.
Avoiding a situation where a leg would be severed and he'd be trapped, he immediately deactivated the Eight Gates state. While still in mid-air, he condensed four chakra needles in his palm and inserted them into his Yintang, Jingming, Zanzhu, and Taiyang acupoints in rapid succession. Simultaneously, he ripped off a talisman hidden behind his ear.
By using the chakra needles to block the meridians connecting to his eyes, he severed the ocular link and disrupted his central nervous system. Then, he activated the Sealing Binding Array previously carved onto his body.
The only Byakugan Yu could still see out of instantly plunged into darkness.
It was then that Yu, staring with a hollow, white, single eye, arrived before the Main Branch member.
A small hand gently took his. Holding up his palm, which glowed with the Delicate Illness Extraction Technique, she guided it toward the eye sockets of the Main Branch member, Hyuga Genko.
At the same time, the Caged Bird Seal was triggered!
The Ram seal formed by Hyuga Genko immediately sent the signal to activate the Caged Bird curse!
But that command was quickly distorted within Yu's chaotic central nervous system, warped into the activation of the Sealing Art: Sealing Binding Array.
The array carved into his body triggered a fraction of a second before the Caged Bird could properly execute. It only bought Yu less than half a second, but it was enough.
The Caged Bird Seal erupted!
Intense, agonizing pain surged!
However, Yu didn't even flinch. Years of experimentation had long since allowed him to locate the central nerves where the Caged Bird triggered pain, and he had severed those sensory pathways in advance.
Anyone who was frequently subjected to the Caged Bird knew that its activation followed a specific sequence: first, it inflicted pain; then, it destroyed the eyes; and finally, it annihilated the brain.
It was like a logically precise program, executing every step swiftly and accurately.
But what would happen if that program encountered an unexpected error?
Right now, Yu was gouging out Hyuga Genko's two Byakugan one after the other. He counted the seconds in his mind, feeling every sign of the Caged Bird's activation.
The chakra within his body began to gather uncontrollably toward the Caged Bird Seal. Very quickly, a surge of teal chakra—the same color as the seal—erupted from the mark.
The moment this teal chakra appeared, it rushed through the meridians toward Yu's eyes.
His remaining left eye began to swell, compress, and twist within the socket!
In the next instant—
Bang!
Yu's last Byakugan imploded within the socket, turning into a puddle of vitreous humor.
Immediately after, the teal chakra surging from the Caged Bird Seal on his forehead bypassed the mangled ocular meridians and, in Yu's perception, raced toward his brain.
Yu's heart tightened; he felt as if a cold snake were crawling up his spine.
He immediately raised his palms, stuffing the two Main Branch Byakugan into his empty sockets. In a span of time measured in microseconds, using a technique that completely ignored post-operative aesthetics in favor of raw speed, he reconnected the two Byakugan to the optic nerves, the tiny neurovascular tissues, and the tendons between the four rectus muscles.
Finally, he reattached the eye globes to the remnants of the rectus muscles he had stripped away!
A second later...
The teal chakra of the Caged Bird Seal, which had been rampaging toward Yu's brain, suddenly came to a halt.
It was only a single millimeter away from his brain!
At this moment, "it" seemed almost confused.
"It" had clearly destroyed Yu's Byakugan. The next step was to destroy the brain, sending Yu into immediate brain death.
But just then, a pair of extremely high-purity Byakugan had suddenly appeared in Yu's eye sockets!
For a moment, this chakra was stuck in a loop: choosing between [Returning to destroy the Byakugan] or [Proceeding to destroy the brain].
The person who had designed the logic of this cursed seal likely never imagined someone would exploit a "bug" in such a terrifyingly narrow window of time.
Ultimately, the teal chakra lingered between the meridians of the eyes and the brain. It hovered back and forth...
Then, it suddenly surged back into the newly transplanted Byakugan!
"Not good!"
Yu's heart hammered against his ribs.
Right now, the Caged Bird had not executed the command to destroy his brain, but had chosen to return.
That meant it was very likely going to re-execute the sequence: destroy the eyes, then destroy the brain!
Yu had no more Byakugan left to gouge out and replace to exhaust this surge of Caged Bird chakra. Furthermore, his current environment did not allow for another attempt at eye surgery.
Outside, the battlefield still raged!
Yu's heart felt like a bowstring drawn to its limit. He didn't even dare to breathe, fearing that a single gulp of air would cause his brain to explode in this incredibly unstable, dangerous state!
However...
To Yu's utter surprise—
As if touching some indefinable boundary, the teal chakra shed its previously feral nature. In an incredibly gentle, soothing manner, it began to slowly stroke the pair of Byakugan Yu had just implanted.
The moment they made contact, this teal chakra—which was far higher in quality than any type of chakra Yu had ever seen—merged into his eyes like a silent spring rain.
Hazy white light gradually filled Yu's vision.
His eyes felt slightly itchy.
And this new pair of Byakugan that now belonged to him seemed... to be undergoing a subtle, profound transformation.
Within the eyeballs, a brand-new "organ" was beginning to grow.