Tomioka Giyu stayed at Headquarters for two days.
During that time, he didn't see the other Hashira again, nor did he run into Kocho Shinobu.
Aside from handling a few necessary administrative tasks, he spent most of his time in his assigned quarters—either polishing his Nichirin Sword or sitting quietly in meditation, tracing the flow of Water Breathing through his body.
The Eleventh Form, Dead Calm, still needed refinement, especially in its duration and the strain it placed on his breathing. There was much room for improvement.
On the morning of the third day, a member of the Corps came to knock on his door.
"Tomioka-sama, Oyakata-sama requests your presence."
Giyu stood, straightened the dark blue haori draped over his shoulders, and followed the escort down the corridor.
Ubuyashiki Kagaya's room was at the far end of the compound, the air faintly scented with medicinal herbs.
When Giyu slid the door open, the master sat by the window. Sunlight filtered through the paper screen, casting a soft glow over his pale face.
"Tomioka-kun, come, have a seat."
Kagaya's voice was gentle and frail from illness, yet carried a steady clarity.
Giyu knelt across from him, head slightly lowered. "Oyakata-sama."
"I've already heard about you."
Kagaya smiled faintly. Though his sight was fading, his perception seemed to reach through everything around him.
"An Instant to slay a Lower Moon… and to have created an Eleventh Form for Water Breathing. Urokodaki-san has trained quite the remarkable student."
"Just luck," Giyu murmured.
"Luck," Kagaya said with a quiet laugh, "is also a kind of strength."
Then his tone shifted, calm but focused.
"I called you here today to assign your jurisdiction."
He extended a hand. A waiting attendant stepped forward, offering him a map.
Kagaya's fingers moved slowly across the surface until they stopped on one region. "The Echigo area in the Hokuriku region—it will be under your charge."
Giyu leaned forward to look.
The Echigo region was mountainous and cold, its villages scattered and remote. For the Demon Slayer Corps, it had always been a difficult area to manage.
The demons there were adapted to the severe climate, often elusive, making yearly mission success rates unusually low.
"The situation there is complicated," Kagaya continued, as though reading his thoughts.
"But I believe you'll manage well. Your Breathing Style is Water—able to wear down stone, and to freeze when needed. That quality may serve you well against the demons of that region."
"Understood," Giyu replied without hesitation.
"I'll protect Echigo."
Kagaya nodded gently.
"Good. I've also assigned you three subordinates—experienced swordsmen. They'll be waiting at the Echigo outpost. They'll assist with reports, information gathering, and daily operations."
"I understand."
"That's all, then. Prepare yourself and depart once you're ready."
Kagaya's voice softened again. "Travel safely."
Giyu bowed deeply before taking his leave.
Just as he turned a corner in the corridor, someone came from the opposite side—and the two nearly collided.
The man before him was tall and broad-shouldered, wearing the standard black uniform. Short, silver-white hair framed a face scarred with several jagged marks.
But it was his eyes that drew attention—sharp gray-blue irises glaring like those of a beast whose territory had just been challenged.
Shinazugawa Sanemi.
Giyu stopped walking.
By this point in time, Sanemi should have just passed the Hashira assessment, though not yet officially appointed as the Wind Hashira.
In his previous life, Giyu's first encounter with him had been during a Hashira meeting. From the very start, Sanemi had been openly hostile, their clashes frequent afterward.
"So, you're the new Water Hashira?"
Sanemi's voice was rough, openly provocative.
"Tomioka Giyu?"
"Yes," Giyu answered evenly.
Sanemi's eyes swept over him, his expression filled with disbelief. "I heard you killed a Lower Moon in an instant. Sounds to me like that demon was just weak."
Giyu stayed silent.
He understood Sanemi's temperament—the more you argued, the more it fueled his temper.
"What's the matter? Cat got your tongue?"
Sanemi took a step forward, hostility radiating from him in waves.
"I'll tell you this—being a Hashira isn't something you earn with luck. If you're not strong enough, the demons will tear you apart before long."
Giyu met his gaze steadily.
Sanemi's strength was undeniable. The violent and razor-sharp nature of Wind Breathing placed him among the most aggressive of the Hashira.
Yet now, he still carried the raw edge of youth. His attacks were powerful but lacked composure.
If honed further, his potential could climb much higher.
In the battle at the Infinity Castle, Sanemi had fought to the death to protect Kamado Tanjiro.
If he had been stronger then… maybe he wouldn't have had to pay such a heavy price.
A thought formed in Giyu's mind.
"Want to test it?" he asked suddenly.
Sanemi blinked. "Test what?"
"A spar," Giyu said plainly. "Right here. We'll stop before it gets serious."
Sanemi's eyes lit up instantly—the unmistakable gleam of a fighter thrilled by challenge.
He grinned, baring sharp teeth. "You want to fight me? Fine! I've been dying to see how strong this overhyped Water Hashira really is!"
A few nearby Corps members gathered, drawn by the tension.
Some looked like they wanted to intervene, but seeing Sanemi's bloodthirsty stance, they hesitated and held their tongues.
Giyu slipped off his haori and handed it to one of the onlookers, standing in his black uniform.
He stepped into the courtyard, facing Sanemi across the open ground.
"Come," he said quietly.
Sanemi let out a low chuckle and suddenly drew his blade.
His Nichirin Sword was a rare pale green, long and narrow, its edge gleaming coldly under the light.
"Wind Breathing, First Form: Dust Whirlwind Cutter!"
The instant his words fell, Sanemi's figure vanished into a blur. A sharp howl tore through the air as he lunged straight toward Giyu's face.
His speed was astonishing—far beyond that of ordinary swordsmen, even nearing the level of a Hashira.
This was the explosive force of Wind Breathing.
But to Giyu's eyes, every motion of his attack was perfectly visible.
He didn't retreat or block.
Instead, his foot shifted lightly, his body gliding half a foot to the side, moving as fluidly as flowing water—just enough to slip past Sanemi's blade.
At the same moment, his own Nichirin Sword rose in a soft, upward motion.
A crisp "ting!" echoed.
Sanemi felt a subtle force twist against his blade; the edge veered slightly upward, opening a gap across his chest.
Startled, he instantly switched forms, wrist twisting as the blade curved back in a wide slash.
"Wind Breathing, Second Form: Claws-Purifying Wind!"
Three arcing blades of wind tore through the air like claws, sealing every path of retreat around Giyu.
Giyu drew a deep breath, his Water Breathing surging through his body in rapid rhythm.
"Water Breathing, Third Form: Flowing Dance!"
His movements turned light as rippling water, his feet gliding between the blades with flawless precision—untouched.
At the same time, his sword moved in harmony with the rhythm of his breath. Each swing met Sanemi's strikes with steady, fluid power, the impacts gently redirecting the Wind Breathing's momentum.
Sanemi's attacks grew faster, more ferocious.
Each form of Wind Breathing carried its own stormlike violence; the blades wove a furious net of slashing air, pressing Giyu back step by step.
"What's wrong?! Can't do anything but dodge?!"
Sanemi roared, veins bulging across his forehead.
"Show me the strength that killed a Lower Moon!"
Giyu's expression stayed calm. He was waiting.
Though Sanemi's strikes were fierce, his breathing had already begun to falter.
The Wind Breathing's strength came at the cost of control—such relentless offense couldn't last.
Now.
When Sanemi unleashed Wind Breathing, Fifth Form: Cold Mountain Wind—intending to freeze Giyu's movements with sheer force—Giyu struck.
He didn't evade this time. He stepped forward, right into the storm of blades.
"Water Breathing, Eleventh Form: Dead Calm!"
A ring of pale blue water burst to life around him, spinning rapidly, its current forming an unshakable barrier.
Sanemi's blade crashed against the water ring—but it was like striking a vast lake. The power of his swing dissolved instantly, swallowed by the rotating flow.
His eyes widened in disbelief. He had never seen a technique like this.
Before he could recover, Giyu had already closed the distance.
The flat of Giyu's blade brushed past his neck, trailing a cold gust that cut the air—without drawing blood.
"You lost."
Giyu's quiet voice reached his ear.
Sanemi froze in place, still locked in his mid-swing stance. The anger and frustration on his face stiffened.
He could feel it—if that blade had moved even an inch deeper, he'd already be dead.
The courtyard fell silent.
The surrounding Corps members stared, dumbfounded. No one had expected such an even fight to end in an instant.
Giyu slid his sword back into its sheath, the movement smooth and precise.
"Your strength is impressive," he said evenly, his tone calm but earnest. "But your attacks are too hasty. Your breathing's unsteady—it leaves openings. If you can control your rhythm, focus your intent, you'll become much stronger."
Sanemi snapped out of his daze. With a harsh motion, he shoved his sword into its scabbard and turned to leave, his face tight with humiliation.
"Wait," Giyu called.
Sanemi halted, but didn't turn around.
"The demons in the Echigo region specialize in ambushes and concealment. They counter Wind Breathing well," Giyu said.
"If you have time, you should go there for a while."
Sanemi's body tensed. For a brief moment, he stood still—then strode off without a word.
Giyu watched him go, exhaling softly.
That sparring match had been a test—for both of them.
The defensive power of the Eleventh Form, Dead Calm, had surpassed his expectations. Even against the ferocity of Wind Breathing, it held firm.
And Sanemi's strength was as fierce as Giyu remembered—he just needed time and polish.
Sending him to Echigo wasn't just practical. It would help Sanemi grow—and give Giyu another layer of protection for the region.
There were many demons there. With Sanemi's help, they could clear the area faster.
But more than that—Giyu wanted him to become stronger.
In his previous life, the Hashira had fallen one after another. That helpless feeling was something he never wanted to face again.
If he could help even one of them grow stronger, it would add another thread of hope.
Giyu picked up his haori from where it had been set aside and slipped it back on.
The outpost in Echigo was waiting, and time was already running short.
He looked once more in the direction Sanemi had gone, then turned and walked out through the main gates of Headquarters.
Sunlight fell across his dark blue haori, the fabric glinting faintly in its glow.
The wind and snow of Echigo were waiting for him.
And his steps only grew faster, steadier, and more resolute.