"This is getting boring, Renji! You'd better step it up, or you're definitely going to lose."
After battling Renji for so long, Rukia was beginning to feel completely unchallenged.
Rather than keep dragging out the fight, she decided to test the mysterious power of the Nine Stars for herself.
"Gyokkō stirs — the slaughter begins."
At Rukia's command, the icy aura surrounding her vanished in an instant.
In its place, a terrifying killing intent erupted from her body like a volcano.
Rukia seemed to become an entirely different person.
Her beautiful features twisted into something savage, and a bloodthirsty gleam appeared in her eyes.
The horrifying presence radiating from her made her look like a murderous demon unleashed upon the world.
Renji, still fighting her at close range, was immediately caught within that killing intent.
In an instant, it felt as though an enormous mountain had descended on his body.
His movements became unbearably sluggish, and the rapid rhythm of his attacks slowed dramatically.
"What the hell is this ability?"
Renji's teeth began chattering.
This was even harder to endure than being crushed by raw reiatsu.
The feeling of helplessness rose straight from the depths of his heart, as though the attack had been designed specifically to suppress the mind.
"Renji, you'd better block this properly."
Rukia smiled at him.
"If I accidentally cut you to death, don't blame me."
"Yōkō descends — let all things break!"
Rukia's reiatsu exploded outward.
The powerful wave swept across the training ground, while the killing intent surrounding her underwent a profound change.
It became an overwhelming sense of destruction, one that seemed able to reduce everything caught within it to dust.
Rukia stepped through the Seven-Star Steps and vanished like a phantom.
In the blink of an eye, she appeared directly in front of Renji.
Sode no Shirayuki traced a brilliant arc through the air as she brought it down toward his head with unstoppable momentum.
Renji didn't dare underestimate the strike.
He hurriedly drew Hihiō Zabimaru back and wrapped the massive skeletal serpent around himself like a turtle retreating into its shell.
Rukia's blade descended.
Clang!
The strike landed directly against one of Zabimaru's enormous skeletal segments.
A tiny crack appeared across the seemingly indestructible bone.
Then it spread.
The fracture raced outward like a snake, branching into countless smaller cracks until the entire segment was covered in a dense spiderweb.
Crack. Crack. Crack.
A moment later, Hihiō Zabimaru shattered like fragile glass.
Countless bone fragments exploded in every direction and scattered across the arena.
"Th-That's impossible!"
Byakuya and Tetsuzaemon stared with their eyes wide and mouths hanging open.
Neither could believe what they'd just seen.
Rukia's slash had looked almost ordinary, yet it had destroyed Renji's powerful Bankai with ridiculous ease.
It made no sense at all.
"No."
Byakuya's gaze sharpened.
"When Rukia swung her sword, one of the stars along the blade lit up. That strike must have received some kind of enhancement we don't yet understand."
His eyesight was exceptionally keen, and he'd caught the unusual detail immediately.
"So that's what happened…"
Tetsuzaemon belatedly nodded in understanding.
Perhaps Renji had simply been fated to suffer this calamity.
In the original course of events, he'd recklessly challenged Byakuya with Bankai despite the vast gap in their strength.
Unsurprisingly, the battle ended in crushing defeat.
Byakuya had used Senbonzakura Kageyoshi to destroy Zabimaru, leaving several of Hihiō Zabimaru's segments permanently damaged and unable to fully recover.
Earlier, when Kazuma fought Renji at the Senzaikyū, he'd deliberately held back and avoided breaking the Zanpakutō.
Yet fate apparently refused to let Zabimaru escape its inevitable destruction.
This time, though, the damage was far worse.
Zabimaru had been reduced to pieces scattered across the floor.
"My sword…"
"My sword…"
Renji stood motionless, gripping nothing but Zabimaru's remaining hilt.
His eyes were empty, as though his soul had left his body.
The previous exchange replayed endlessly in his mind.
He'd used every ounce of strength he had to defend himself, yet he'd still badly underestimated Rukia's deceptively simple slash.
His gaze slowly fell on the fragments covering the ground, and he looked close to tears.
Once he released Bankai, Zabimaru returned to the form of an ordinary Zanpakutō. Unfortunately, the blade was now covered in countless intersecting fractures.
It looked as though the slightest additional impact would reduce it to a pile of worthless metal.
"Did… did I seriously mess up?"
Rukia finally noticed Renji's devastated expression and realized something was terribly wrong.
This was the first time in her life she'd destroyed someone's Bankai, so she had absolutely no idea how serious the consequences might be.
"Brother-in-law, why is Renji making that face?"
She hurriedly looked toward Byakuya for help.
"He only lost to me. Does he really need to look like his whole life is over?"
At a moment like this, the only person she could rely on was her far more experienced brother-in-law.
"Rukia, you have caused a serious problem."
Byakuya's expression became grave.
"When a Zanpakutō is damaged this severely while in Bankai, the damage is permanent and cannot be reversed."
"You've destroyed Zabimaru to such an extent that Renji may no longer be capable of even an ordinary release."
"Then… what do we do?"
Rukia immediately panicked.
What had begun as a simple sparring match had turned into a disaster.
If Zabimaru couldn't be repaired, Renji's future would be ruined.
How could he continue serving as a Shinigami without a working Zanpakutō?
"Renji, I'm sorry!"
Rukia hurriedly bowed deeply to him.
"I didn't know the consequences would be this severe. This is my fault!"
"It isn't your fault."
Renji finally came back to his senses, though he now looked far more dejected than before.
"I was simply too weak. If I'd been stronger, Zabimaru wouldn't have ended up like this."
No one could easily accept seeing their Zanpakutō reduced to such a miserable state.
...
"I'm going to the First Division to find Kazuma-sensei right now. He'll definitely know what to do!"
Rukia was thoroughly panicking by this point.
She placed all her hopes on Kazuma, having long since formed the impression that her teacher could do practically anything and solve any problem with ease.
"Renji, bring your Zanpakutō and come with me to the Twelfth Division," Byakuya said calmly.
"Captain Kurotsuchi may have some way to repair it."
When it came to fixing Zanpakutō, the Department of Research and Development had the necessary expertise.
Some problems were simply best left to specialists.
"Captain… do you really think Captain Kurotsuchi can fix it?"
A faint spark of hope returned to Renji's previously lifeless eyes.
He clutched Zabimaru's damaged hilt as though it were the only thing keeping him alive.
Mayuri had become his last hope, and Renji desperately prayed a miracle might still be possible.
"I cannot promise anything," Byakuya replied with a slight shake of his head. "He must inspect the damage before he can say whether it can be repaired. Regardless, trying is better than sitting here doing nothing."
He then turned toward Rukia.
"We'll split up. You go to the First Division and find Kazuma. I'll take Renji to Captain Kurotsuchi."
Byakuya mostly sent Rukia away so she'd have something to do instead of drowning in guilt.
He didn't genuinely expect Kazuma to know how to repair a shattered Bankai.
...
First Division
"Sensei! Something terrible happened! Sensei!"
Rukia stormed into the First Division compound, shouting as she ran.
Yamamoto had been about to give Kazuma a rather severe interrogation when Rukia's cries reached them.
"Chōjirō, go see what the commotion is about."
Sasakibe Chōjirō left at once and soon returned with Rukia.
"Rukia, what could possibly justify making such a disturbance in the First Division?"
Yamamoto looked displeased.
Running through his division screaming at the top of her lungs was hardly proper behavior.
"Sensei, I broke Renji's Zanpakutō."
Rukia paused to catch her breath, then looked hopefully at Kazuma.
Surely he'd have a solution.
"That's all?"
Kazuma's anxiety immediately disappeared.
"A Zanpakutō can recover naturally if its blade breaks. Why are you panicking over something so minor?"
For a moment, he'd genuinely thought his disciple had caused some enormous disaster.
"It isn't like that! I shattered Renji's Zanpakutō while he was using Bankai! Even after it returned to its sealed form, the whole blade was covered in cracks!"
"You did what?!"
Yamamoto, Kazuma, and Chōjirō all stared at her in disbelief.
For a moment, they wondered whether they'd misheard her.
The claim sounded absurd.
How could someone at Rukia's current level destroy a Zanpakutō in its Bankai state?
"It's true!"
Rukia was close to tears.
Why did no one believe her when she was telling the truth?
"How exactly did you break it?" Kazuma asked, finally starting to believe her after seeing her aggrieved expression.
"I just… used Yōkō's power and gave it one light slash. Then Hihiō Zabimaru shattered."
"It shattered?"
Rukia nodded.
"My dear disciple…"
Kazuma's vision went dark.
"You really won't be satisfied until you've driven me into an early grave, will you?"
Was the destructive power of Yōkō something she should casually test on another person's Bankai?
And what did she mean by one light slash?
She'd obviously struck with everything she had.
Otherwise, there was no way Hihiō Zabimaru would have been reduced to fragments.
"You used that unusual star power?" Yamamoto asked, showing considerably more interest in that detail than in Zabimaru's condition.
"Its destructive force is truly that great?"
"Yes, Captain-Commander."
Rukia lowered her head guiltily.
"I still can't control it properly. I only wanted to test what it could do, and I never expected the consequences to be so severe."
"Where is Renji now?" Kazuma asked.
"My brother-in-law took him to the Department of Research and Development. He said Captain Kurotsuchi might be able to repair Zabimaru."
Kazuma shook his head.
He wasn't looking down on Mayuri's technical ability.
If Zabimaru merely had a chip or a crack, Mayuri might have been able to do something.
But if the Zanpakutō was already on the verge of crumbling completely, it was beyond him.
Their only real hope would be to reach Squad Zero and seek out Nimaiya Ōetsu.
...
That was exactly what happened.
After Byakuya brought Renji to Mayuri, the scientist gave the nearly destroyed Zabimaru a brief examination before declaring there was nothing he could do.
"This is utterly ridiculous! It completely defies common sense!"
Mayuri burst into laughter.
"I know Kuchiki Rukia's former abilities quite well. How could she possibly have reached such a level in so little time?"
He suspected they were making fun of him.
As far as Mayuri was concerned, Byakuya had probably destroyed Zabimaru himself and was merely using Rukia as a convenient scapegoat because he didn't want to admit it.
Byakuya frowned and carefully explained everything that had recently happened to Rukia.
Unfortunately, he didn't seem to realize just how irresistible that information would be to the mad scientist in front of him.
"Something like that truly happened?"
The moment Byakuya finished, Mayuri's chest began rising and falling like a bellows. Every breath came heavy and rapid.
"Captain Kuchiki, you had better not be teasing me!"
"Rukia… Rukia…"
Mayuri looked as though someone had injected pure excitement straight into his veins.
His body trembled uncontrollably as he began waving his arms, repeating her name again and again.
At that moment, everything else ceased to exist in Mayuri's eyes.
There was only Kuchiki Rukia — the perfect research specimen waiting to be studied.
Renji, Zabimaru, and everything else had instantly become irrelevant.
"Tell me where Rukia is!"
Mayuri shrieked, his voice as sharp and unpleasant as the cry of some nocturnal bird.
In truth, Rukia wasn't even the specimen he wanted most.
Given the chance, Mayuri would gladly capture Kazuma too, slice him into thin sections, and study every piece.
Unfortunately, with his current strength, that idea was nothing more than a fantasy.
Mayuri might have been insane, but he wasn't stupid. He knew exactly how wide the gap between himself and Kazuma was.
He was nowhere near strong enough to handle that man.
For a scientist, death meant the end of everything. There could be no further research if the researcher himself was gone.
No matter how tempting the idea, Mayuri could only set it aside for now.
"She is currently at the First Division," Byakuya said coldly. "Captain Kurotsuchi is welcome to go there and bring her back personally. I certainly won't stop you."
He watched Mayuri's near-manic excitement with quiet contempt.
Byakuya had already worked out what was happening.
The scientist's desire to experiment on Rukia had completely overtaken him.
He no longer cared in the slightest about Renji or the Zanpakutō about to crumble in his hands.