(T/N: Hello everyone! Sorry for the recent lack of updates on this novel, and thank you so much for your continuous support! Starting now, I'll be following a set schedule: 3 chapters a day. Please look forward to it!
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Katori Nanatsuki's figure swept across the ground, drawing a black blade embedded in the earth.
With a single slash, a streak of Flowlight cut Kagehime cleanly in two.
Even as her body was split, Kagehime quickly reformed, using the shadows to rapidly close the distance to Nanatsuki.
After activating Shunkō, Nanatsuki could instantly widen the gap between them.
Before Kagehime could even swing her blade, Nanatsuki had already vanished from his original position. While moving, he pulled another black blade from the ground and unleashed another streak of Flowlight.
"The number of black blades hasn't decreased at all…" Nanatsuki muttered as he swallowed a Spirit-Converging Pill.
He had been locked in combat with Kagehime in the Sakkise Training Grounds for a full day. His task: find the one black blade among them that could defeat her.
He had tested many blades already, but the number stuck in the ground had barely diminished.
"Finding that blade won't be easy. Besides, it doesn't stay in the same place, you know?" Kagehime giggled playfully.
Nanatsuki narrowed his eyes at the blades scattered across the training field. Every so often, they would revert into shadows, then reappear elsewhere on the ground—even those he'd already touched.
Kagehime was constantly reshuffling.
Another streak of Flowlight sliced her body again.
But this time, instead of rejoining, her split halves each transformed into a fully formed Kagehime.
"How boring. I can't even keep up with Master. I guess it's time to increase the difficulty!"
The two Kagehimes each drew a black blade and sank into the shadows on the ground.
In the next instant, one of them emerged right beside Nanatsuki and slashed at him.
Whoosh—Nanatsuki evaded with Shunpo.
But just as his figure reappeared on the other side, the second Kagehime rose from the shadow behind him.
She swung her blade swiftly toward his back.
In that split second, Nanatsuki suddenly raised both hands and clapped them together—clamping the incoming blade.
At the same moment, a faint smile appeared on his face.
"This is the one!" Nanatsuki switched to gripping the spine of the blade with one hand, then reached for the hilt with the other.
Kagehime's face froze in shock as Nanatsuki grasped her hand—and flipped the black blade.
Schlick—The blade plunged into her body, causing her form to tremble slightly.
This was it—the blade that could defeat Kagehime!
"How did you figure it out, Master?" Kagehime asked, curious.
She had been reshuffling constantly, shifting the blades' positions to waste his efforts.
Yet he found it within just one day.
"With this." Nanatsuki pulled out a glass vial and shook the black-and-red substance inside.
He smiled. "Every blade I touched carried traces of Hollow Particles."
"You are my Zanpakutō. Our spiritual wavelengths are identical—so you can't be differentiated through spiritual perception alone."
"But Hollow Particles are different. Once attached, they shine like stars in the night—easy to spot."
"Right now, every blade on the ground is coated with Hollow Particles. Only the one in your hand slipped through."
Kagehime's eyes lit up in realization. "I see! Master is so clever!"
Her body slowly melted into shadow. The shadows across the training ground rapidly shrank.
The Sakkise Training Grounds quickly returned to normal.
Nanatsuki's Zanpakutō returned to his hand.
At that moment, a sensation rose in his heart—he had achieved Bankai.
He raised the Zanpakutō and turned the blade downward.
"Bankai—Shosō Eijin!"
He released the hilt, and the blade fell—but rather than stabbing into the ground, it melted like ink and sank below.
The surface blackened once more. Shadows spread outward at a speed invisible to the naked eye.
It wasn't just the ground. The entire space became covered in shadow.
The shadow spread swiftly through the Sakkise Training Grounds, continuing outward.
In the adjacent lab—
Aizen Sōsuke and Hoshino Rie were still in the lab finishing their experiment reports.
Aizen had already completed his. He lingered to test a few hypotheses using leftover fragments of Reishi Shells.
Hoshino Rie sat across from him, wracking her brain to flesh out the report content.
On Aizen's desk sat a rabbit. He injected it with Hollow Particles extracted from the Reishi Shell remains.
"Hollow Particles seem extremely aggressive…" Aizen observed as the rabbit began to mutate.
Its eyes turned black and red. Rationality was quickly replaced by savagery. Its body began swelling, growing to the size of a lamb.
But just then—something strange occurred.
The lab was engulfed in black shadow. In its place remained only pitch darkness.
Aizen reacted swiftly. As the shadow appeared, he instinctively unleashed his Reiatsu to resist the change.
It was useless. The shadow advanced unimpeded.
Walls and floor vanished. They now stood in an endless black void.
Aizen quickly calmed himself and scanned the area—he found Rie and the mutated rabbit nearby.
She still held her pen, dazed by the sudden transformation.
But they soon sensed their teacher's spiritual pressure.
Without the Sakkise blocking it, Katori Nanatsuki's immense Reiatsu surged forth.
"What is this?!" Aizen was shaken. His teacher's Reiatsu was overwhelming. He had only sensed such strength from Captains.
He lifted his hand and pushed up his glasses, hiding the shock in his eyes.
Sensei… had reached Captain-class Reiatsu!
Since mastering Shikai, Aizen had used Kyōka Suigetsu to infiltrate Seireitei, gaining much knowledge.
He'd thought Nanatsuki-sensei was just a strong Vice-Captain—but far from Captain level.
But now, he was stunned.
'So you're hiding your strength too, Sensei… how deep does your power go?' Aizen thought.
The rabbit trembled in a ball on the table.
The savage black-red eyes were now filled with fear.
"It's afraid?" Aizen smirked. He had thought the mutation erased all instincts but hunger.
"Fear is instinct too, Sosuke."
Nanatsuki's voice sounded beside him.
Aizen's pupils contracted. He hadn't sensed his approach at all.
"Sensei's spiritual pressure is so overwhelming, even mindless creatures fear it," Aizen muttered.
"It's just Captain-class Reiatsu," Nanatsuki said casually, withdrawing his pressure.
Aizen and Rie sighed in relief.
"Ugh—so strong…" Rie gasped. "Sensei… really is at Captain level?"
She couldn't assess the Reiatsu directly, but it felt like her heart was being squeezed.
As Nanatsuki retracted it, the rabbit lifted its head again, aggression returning.
With no real intellect, it couldn't understand what had happened. It didn't know the pressure came from Nanatsuki.
It charged, horn first—
—and was instantly impaled by a pitch-black blade rising from the floor.
The blade pierced through the rabbit, continuing to rise.
A black silhouette holding the blade emerged from the floor.
"Is this… Sensei's ability?" Aizen was startled. The figure looked familiar.
It was… his own shadow.
"Yes. This is my created Shadow Space. All shadows here are mine to command," Nanatsuki nodded.
"If Sensei can attack using shadows, his swordsmanship just became even more diverse…" Aizen muttered.
Nanatsuki smiled faintly. He didn't reveal more.
In truth, his Bankai had far greater potential.
He glanced at the shadow-Aizen's weapon—Kyōka Suigetsu, now pitch black.
The true strength of his Bankai… was the ability to replicate a portion of the shadow owner's powers.
Meaning: through Aizen's shadow, he could use Kyōka Suigetsu.
Though only a fraction of the original power—still, it gave him incredible versatility.
Depending on the opponent, he could replicate 10% to 50% of the ability.
The stronger the original, the weaker the replication.
Nanatsuki had the shadow-Aizen walk over.
He pulled the rabbit from the black blade and asked, "Sosuke, you injected it with Hollow Particles?"
"Yes. Extracted from the Reishi Shell remains," Aizen replied. "Its body didn't break down like the shells did. Perhaps the particles changed inside the shell."
Nanatsuki thought aloud: "Then maybe these aren't pure Hollow Particles anymore."
"That shell was once a Shinigami, even if soulless. It originated from one."
"It's possible Shinigami and Hollow particles fused and changed. This deserves deep study."
"Set up control groups. See if it's unique."
"I still have enough Hollow Particles for three or four more tests," Aizen nodded.
"I'll be going to Hueco Mundo next week. I'll collect more Hollow-related samples—maybe even bring back a live Hollow. The ones extracted from Divine Armament might be different," Nanatsuki said.
"You're heading to Hueco Mundo?" Aizen asked.
"Yes. Kensei and the others' graduation exam is set—it'll take place there."
"Graduation exam… in Hueco Mundo?" Rie said, worried. "Isn't that too dangerous?"
"Early graduation is harder. Don't worry—they're not fighting. Just delivering supplies to the expedition force," Nanatsuki reassured her.
He canceled the Bankai. The shadow space dissolved instantly.
All lab equipment remained intact.
Now that he'd mastered his release, he felt much safer heading into Hueco Mundo—even facing Adjuchas-class Menos.
Originally, he activated Bankai in the sealed Sakkise field—but he now stood in the lab.
Nanatsuki pondered.
The shadow space ignored barriers and enveloped the space. While active, he could move freely. When deactivated, he appeared at the shadow's location.
Meaning—he could pass through obstacles.
'Could this bypass the particle barriers of Muken or the Wandenreich?' he wondered.
If his space could breach those, he could infiltrate silently.
He needed to test it—but not with such dangerous targets yet.
There was another barriered location—less dangerous.
Nanatsuki left the lab and headed for Seireitei.
He donned a hooded cloak.
He'd taken it two years ago from remnants of the Kasumioji Clan who had attacked him and his students.
To test his Bankai, he'd need to release Reiatsu.
The cloak could mask spiritual pressure.
Outside Seireitei, he found a quiet spot.
Facing the Shakonmaku, he activated Bankai again.
"Bankai! Shosō Eijin!"
His Zanpakutō melted into ink and spread at invisible speed.
The shadow space expanded rapidly, crossing the Shakonmaku and continuing outward.
Success!
Nanatsuki's heart leapt. The shadow had covered the barrier.
Shadow space existed in a separate layer of reality—even when passing through the barrier, it caused no damage.
He extended a hand through where the barrier should be—nothing happened. No burning, no disintegration.
He stepped forward, walked several meters, then deactivated the Bankai.
The space dissolved instantly.
The Shakonmaku reappeared, untouched.
But Nanatsuki had passed through completely unscathed.