Chapter 5: Lake Ashi
Nestled deep within the mountains near Hakone lay a clear volcanic lake, its surface calm and mirror-like beneath the moonlight. Pine and cedar forests encircled its shores, and in the distance, the reflection of Mount Fuji shimmered faintly upon the water.
This was Lake Ashi.
On the surface, it appeared no different from any other scenic landmark.
But in truth, this lake served another purpose entirely.
It was one of the Final Selection grounds of the Demon Slayer Corps.
Alongside Fujikasane Mountain and Kurobe Gorge, it functioned as a proving ground—where candidates either earned the right to fight demons… or died trying.
---
"There are quite a few more examinees this year."
"That's a good thing, isn't it? With more people, dealing with those damned demons should be easier."
"Lower your voice. Don't let Lord Kagome hear you."
Near the torii gate by the lake, several figures whispered among themselves.
Their faces were wrapped in cloth, their movements light and restrained.
They were the Hidden—the logistical support unit of the Demon Slayer Corps.
They handled everything from battlefield cleanup and post-battle support to intelligence relay.
Maintaining the Final Selection grounds was also part of their responsibility.
Standing before them was a young man with a cool, aloof bearing.
A simple ebony hairpin loosely tied his hair, with several pale strands cascading down his shoulders. He wore a pristine white robe and hakama, layered beneath a dark purple haori.
His name was Kagome Konomori.
A member of the Kanagashi family—a priestly clan that had maintained close ties with the Ubuyashiki family for generations—he served at Hakone Shrine.
Today, however, his role was different.
He was the presiding officer of this Final Selection.
Traditionally, such ceremonies were overseen by members of the Ubuyashiki family themselves. But with their numbers dwindling, the responsibility had gradually been passed to allied priest families.
Kagome did not particularly like the Ubuyashiki family.
But between his family's obligations and his personal hatred of demons, he accepted the duty.
He ignored the whispers behind him and gazed toward the lake.
Several wooden boats were slowly approaching through the night.
"…Looks like this is the final group."
As swordsmen of varying heights disembarked, Kagome paused briefly before stepping forward.
---
"…So this is the Final Selection my cheap master mentioned?"
As soon as he stepped onto the shore, Kucha Natsumi surveyed his surroundings with curiosity.
Torii gates.
Blooming wisteria.
Masked figures standing silently.
And a priest who looked suspiciously like a charlatan.
As for the other examinees:
Hida Shouta (Level 27) — Fire Breathing LV.2
Kitetsu Saburo (Level 31) — Water Breathing LV.1
Shusui Reiko (Level 22) — Water Breathing LV.1
Tenyu Zan (Level 19) — Thunder Breathing LV.1
…
Their faces were filled with hatred and hidden stories, giving the illusion of seasoned warriors.
In reality, among the twenty-odd candidates present, fewer than five had reached Level 30.
Only one person had achieved Breathing Technique LV.2 (Basic Understanding).
Compared to Kucha's own stats—nearing forty, with a Level 2 breathing technique—the rest could only be described as… fodder.
Before arriving, he hadn't been especially confident.
Now?
Wasn't this practically guaranteed?
In his view, any organization locked in a high-mortality conflict had to balance recruitment and losses. If the casualty rate exceeded the intake, collapse was inevitable.
Assuming the Demon Slayer Corps numbered several hundred active members and lost more than half each year—even excluding support staff—they would need close to a hundred new swordsmen annually.
Five selection sites, held twice a year…
At least ten survivors per site were needed just to break even.
Which meant nearly half the candidates here would be eliminated.
Kucha considered the Oni he'd encountered days earlier.
Against that level of enemy, he could probably handle two or three candidates attacking him together.
Multiple demons would certainly claim lives—but overall?
This was manageable.
He then glanced toward the examiners.
Yama no Naka (Level 11) — Rock Breathing LV.0
Akimichi (Level 18) — Wind Breathing LV.1
Nara (Level 9) — Water Breathing LV.0
…Weaker than most of the examinees.
So the examiner was just an ordinary human?
Meaning they wouldn't interfere with safety or order at all?
As Kucha pondered this, the person he'd internally labeled "ordinary" cleared their throat.
"Young swordsmen," Kagome said calmly, "thank you for gathering here tonight."
"You now stand at a crossroads of fate. Ahead lies Lake Ashi—your Final Selection ground."
"I will now explain the rules."
"This mountain range is enclosed by ever-blooming wisteria barriers. Within it, demons captured alive by the Corps are imprisoned."
"Rest assured—they cannot escape."
"Your task is simple."
"Survive here for seven days."
"If, after seven days, you can leave this mountain, you will pass the selection."
His gaze swept across the assembled candidates.
They were all young.
The youngest looked barely over ten.
Yet not one showed hesitation.
"The wisteria is both a barrier and a cage," Kagome continued.
"The demons cannot escape—and neither can you avoid them."
"If you feel you cannot endure, you may withdraw at any time and return to this torii gate."
"But whatever you choose, remember this."
"Grip your sword tightly."
"And guard your heart."
With that, he stepped aside, revealing the mountain path beyond the torii gate—already swallowed by darkness.
"I wish you all good fortune."
Silence followed.
Each swordsman present had trained for at least six months. Nearly all carried blood-deep hatred for demons.
Still, the unknown was frightening.
Especially now, with these wisteria-bound mountains redefined as a place of death.
No one wanted to retreat—but everyone needed a moment to prepare.
That was when a voice spoke up.
"If no one's going, I'll head in first."
Kucha Natsumi drew his Nichirin Blade, gave a brief nod, and stepped past the torii gate without looking back.
This wasn't a PvP arena.
It was a PvE survival event.
For him, there was no tension—only excitement.
A mountain full of demons trapped by wisteria?
That was practically a limited-time high-experience dungeon.
Why wait around and let others steal kills?
After taking only a few steps, Kucha suddenly stopped and turned back.
"By the way," he asked casually, "examiner—if I kill all the demons in this mountain…"
"…you won't charge me compensation, right?"
Kagome blinked.
Examiner?
Some sort of slang?
"If you can do that," he replied after a moment, "then there's naturally no issue."
"These cannibals don't feel pain. Killing them all is fine."
"Other Demon Slayers will replenish the stock periodically."
Hearing this, Kucha finally felt at ease.
Good.
Now he could grind without restraint.
Turning back, he disappeared into the darkness.
Perhaps it was his eccentric words.
Or his complete lack of hesitation.
Whatever the reason, the remaining candidates exchanged glances—and the tension broke.
One by one, they stepped through the torii gate.
After everyone had entered, Kagome turned to a Hidden member beside him.
"Yama. That boy who went in first—who was he?"
The Hidden member flipped through the roster, recalling the image.
"The dark blue hair, the waist ornament, that Nichirin Blade…"
"He should be a disciple of Kazami Kyouki."
"Kucha Natsumi. Wind Breathing."
"Both parents were killed by bandits. His younger sister later died to a demon—he was saved by Kazami by chance."
"He's trained under him for about a year."
Kagome nodded slowly.
"…Another child left alone by demons."
Knowing full well it was hell, yet stepping into it without hesitation.
Strong.
Confident.
"Achoo!"
Deep within the mountain, Kucha Natsumi suddenly sneezed.