Fourth Division barracks.
When Unohana Retsu heard that a Central Prison officer named Naraku Sora had come to visit, she pushed aside a few less important tasks.
The more critical surgeries she handed over to her vice-captain, Yamada Seinosuke.
He was a Kaidō specialist whose personality was the complete opposite of Unohana's—often willing to use any means necessary to cure the wounded or sick.
Sometimes that led to even more serious problems.
As a result, his reputation within Fourth Division wasn't very good.
None of that had anything to do with Naraku though. He was here today mainly to call on Unohana and discuss some questions about swordsmanship.
After all, he'd already achieved Shikai—if he kept charging in like before, smashing heads with a few punches and chops like some brainless bruiser, it felt a bit disrespectful to his Zanpakutō.
Given who Unohana had been before she moved to "logistics," Naraku decided to bravely keep the appointment.
There was no one who understood swordsmanship better than she did.
"Naraku-kun, I thought you'd wait a while before coming."
"Judging from the battle during the Araki disaster, it's clear you prefer close-quarters Hakuda, exchanging blows up close."
Walking in front of him, Unohana spoke without looking back:
"However, my understanding of swordsmanship is different from that of other so-called masters. So when we're discussing it, you'll need to pay close attention."
Naraku's wandering thoughts snapped back into focus. A little nervous, he glanced at the shapely figure ahead of him.
But his attention was quickly drawn to the surroundings.
Unohana's private dōjō was surprisingly spacious, completely different from the simple, unadorned style he'd imagined.
Besides paintings of various styles hanging on the walls, there were also a number of extremely advanced-looking devices.
About ninety percent of them were identical to the equipment in Shutara Senjumaru's lab—in fact, some even looked higher-spec.
Especially the spirit energy recovery unit in the corner; it was impossible to ignore.
As if sensing his gaze, Unohana turned slightly and explained with a gentle smile:
"Many years ago, when Senjumaru was still in Twelfth Division, she applied to the Central 46 for permission to form a technical research group for her own interests."
"With her personal genius and the legacy left behind by some of Soul Society's predecessors, she developed all sorts of devices that completely changed how Shinigami live and fight."
"For example, the spirit-body tempering chamber modeled after Fifth Division's kidō recovery room—one restores the mental energy consumed when casting kidō, the other repairs the damage caused by spirit-body training."
"The spirit energy recovery unit can rapidly replenish a Shinigami's depleted Reiatsu, essentially acting as an emergency-treatment tool."
The long base, over two meters in length, was covered in intricate, circuit-like patterns, including sequential Bakudō sigils.
Just from the outside, it looked like a perfect fusion of Kidō and some kind of futuristic technology from the World of the Living.
"These are just secondary," Unohana said softly, her smile lingering. "Since you came to me, I assume you've already prepared yourself."
"Swordsmanship isn't that simple."
Naraku accepted the bamboo sword she handed him. It felt surprisingly heavy—so much so that it almost "pulled" at his arm.
He lowered his eyes.
The moment his fingers closed around the hilt, the atmosphere in the dōjō changed. A faint, heavy pressure began to gather in the air.
Unohana touched her own sword hilt as lightly as if she were brushing a willow branch—quiet and gentle. Meeting Naraku's puzzled gaze, she slowly lifted her face.
Her dark pupils were as mild as always, but a sharpness hidden deep within them slowly surfaced the instant her hand settled on the hilt.
"Naraku-kun. Be careful."
The moment she spoke, a clear sound rang through the dōjō—like a bird taking off from the willow branches, riding the wind into the sky.
Draw, cut, shake the blood, resheath.
The entire iai sequence was completed in an instant. Even with barely any Reiatsu added to it, the strike easily surpassed what the naked eye could follow.
From several meters away, the cool light of the blade fell straight toward Naraku—
like the outline of the moon among a sky of bright stars.
A thin red line appeared at his neck as blood slowly welled up.
From the angle of the cut, if she had put even a little more strength into that strike, his head would have flown.
It was obvious that in pure swordsmanship, Unohana Retsu truly was Soul Society's undisputed number one.
Old man Yamamoto, who relied on nothing but fist and fire, was just bullying people with raw stats.
Not worth counting.
Naraku's eyes grew brighter. Even though he'd almost been decapitated by this terrifying woman, this was exactly what he wanted to learn.
He'd had enough of fighting like a mindless brawler.
"Captain Unohana, I want to learn that."
Unohana's eyes lowered slightly. Just as she was about to respond, something at the edge of her vision caught her attention.
The vivid red line on Naraku's neck had already vanished—without even a trace left behind.
"Your injury…"
Her face showed genuine surprise.
No one knew better than she did exactly how much force she'd used. It wouldn't have caused serious harm, but no ordinary Shinigami could heal so completely in just a few seconds.
This was… not very Shinigami-like.
"I'm just naturally sturdy," Naraku grinned. "The Warden said my spirit body is different from others—my wounds just heal a little faster than normal."
It was the stock line that bad woman had given him, for dealing with people who asked too many questions.
With Shutara Senjumaru backing him, it was more than enough to bluff things through.
Unohana nodded lightly and didn't press the issue.
As Fourth Division's captain, she'd treated more patients than most people ever met. Exceptionally gifted Shinigami weren't outside the realm of common sense.
Especially someone like Naraku—not only chosen by that woman Senjumaru, but also favored by Head-Captain Yamamoto. Having a few "special traits" was only natural.
"Swordsmanship isn't just about techniques."
Unohana seemed to be intentionally testing Naraku's true potential. She began gently explaining the essence behind that previous strike.
"If you could master swordsmanship with simple swinging alone, then all of Soul Society would be masters of the blade."
"So while learning the techniques, you must also try to blend your own perception and will into your Reiatsu—and use your movements to guide that Reiatsu."
"Like this."
She slowly drew her blade, breaking the complete technique down piece by piece, laying it out clearly in front of Naraku's eyes.
It all sounded simple enough when she said it—but when he tried to replicate it, he immediately found it incredibly difficult.
Things like "self-perception" and "will" were vague and intangible. There was nowhere logical to begin.
Fortunately…
Naraku wasn't the type to get stuck in rigid thinking. If he couldn't grasp the "theory" right away, then he'd just break down what he saw using instinct.
Sword, Reiatsu, trajectory, pull…
Some strange understanding surfaced from the depths of his mind.
Click.
The quiet sound of tsuba meeting scabbard rang out, drawing Unohana's gaze.
Reiatsu wrapped around the bamboo sword, then surged upward like a bird taking flight.
At the far end of the dōjō, the solid wall split open with a crack, revealing clear, cloudless sky beyond.
Staring at the boy's confused and helpless expression, Unohana looked stunned for a heartbeat—
Then the corner of her mouth slowly lifted.
A barely audible murmur slipped out:
"How… truly interesting."