"Sun Blade?"
If not for inheriting part of Black Fang's memories, Kawanishi wouldn't have even known a weapon like the Nichirin Blade existed.
Ordinary weapons could wound demons, could slice them up—But even if you chopped a demon into chunks, even if you pounded its flesh into paste, it still wouldn't die.
Demons had bodies tougher than the fiercest beasts, wielded bizarre Blood Demon Arts, and were nearly impossible to truly kill.
The gap between humans and demons seemed too vast—too hopeless to bridge.
Yet in that suffocatingly dark age, the Demon Slayer Corps didn't give up.They stood with nothing but their own flesh and will, and searched tirelessly for a weapon that could kill.
And after countless failures, the Nichirin Blade was born.
Forged from a rare ore called Scarlet Iron Sand, the Nichirin Blade was like any other weapon—until it severed a demon's neck.Only then did the unique properties of the metal activate, obliterating the demon completely.
With the advent of the Nichirin Blade, the Demon Slayer Corps finally had a fighting chance.And from there, they only grew stronger.
Each Nichirin Blade took ten to fifteen days to forge, requiring a smith's full dedication.And because Scarlet Iron Sand was so rare, only official members of the Corps were ever given one.
Kawanishi stared at the blade in disbelief."There was a Nichirin Blade hidden here all along...?"
He rifled through Black Fang's memories, but found no relevant information.Giving up on that, he focused on the weapon in hand.
Neither Black Fang nor his parents knew, but generations ago, one of Black Fang's ancestors had been a demon slayer.That ancestor had personally killed over twenty demons—a respectable feat.
But one day, his squad encountered a Lower Rank of the Twelve Kizuki.Everyone else died. Only he escaped, barely clinging to life.
He dragged his broken body home and, before his death, left these words:
"I've slain many demons in my life. It's not something to boast about, but maybe I saved some lives along the way."
"But you must seal this Nichirin Blade away. And never tell anyone about me."
"I gave everything—my life, my soul—to the Demon Slayer Corps. No, to humanity."
"So now, at the end... let me be selfish."
"I don't want my descendants joining the Corps. Even the Hashira rarely die well…"
"Just live quietly. The odds of meeting a demon are small."
"You'll have a better chance of surviving than we ever did."
"After all, nine out of ten Demon Slayers die young."
"I knew I was going to die the moment I joined. I don't regret it—just wish I'd killed a few more."
"Lord Ubuyashiki… I hope you understand. Please forgive me. I just… don't want my family dying like I did."
And so the Nichirin Blade had slumbered here, untouched in the cellar, never again seeing sunlight.
Until now.
Sching.
The blade slid from its sheath. Despite the centuries, it was flawless—its edge still glinting cold and sharp.
Kawanishi pressed it against his finger. A light push, and blood beaded up.
"So sharp…"
His skin, now a demon's, was tougher than leather. After absorbing Black Fang's power, his body had become like iron—normal blades couldn't even scratch him.
But this one—this blade meant to slay demons—cut through with ease.
This was it. This blade could help him survive.His Shining Wings could also slay demons, but they weren't suited for extended combat.A true weapon gave him an edge in real battle.
If only he'd had this while fighting Black Fang… things wouldn't have been so hard.
Kawanishi swung the blade a few times—then stopped, frowning.
"…I don't know how to use a sword."
Yeah. That's right. Kawanishi, born in the mountains, raised in the woods—He was just a rural bumpkin. The only weapon he'd ever used was an axe.
And compared to sleek, elegant blades, he preferred heavy, brutal, fearsome weapons.He liked axes—big, terrifying, gut-wrenching axes.
Back in his previous life, his favorite video game character was Darius: brutal, relentless, and devastating.Even in this world, his first weapon had been a small hatchet for chopping wood.From the moment he picked it up, it felt right. Natural. Like it belonged in his hands.
Maybe that was talent.
Even Tanjiro's father, Tanjiro himself, had praised his axe work.He could swing, chop, cleave, scoop, slam, twist, and block—all with flawless instinct.
This sword, though?He gave it a few more test swings and immediately hated it.
It felt… wrong.
Kawanishi sighed, as if he could hear fate mocking him:"I gave you the perfect weapon—and you're useless with it."
Suddenly, the small, rust-colored wing mark on his back trembled.
He paused, then nodded slowly. "So… that's how it works?"
He looked down at the blade in his hand and offered a sheepish apology:"Sorry. To fight better… I'll have to change your shape."
"I hope you like your new look."
The blade stayed silent.
"Well, since you're not protesting, I'll take that as consent."
Kawanishi really had no choice.
Even if he did learn swordsmanship, this blade wasn't customized for him—it felt off in his grip.He'd be better off fighting barehanded.
Besides, almost all demon slayers used Nichirin Blades.Demons were wary of swords by instinct.
If Kawanishi used an axe instead, maybe he'd catch them off guard.Or hide his true power until the right moment—let them underestimate him.
His inherited blood demon art, Blade Hell, gave him more than just strength and stamina.It allowed him to form weapons from nothing—perfectly suited to him.
Black Fang's weirdly shaped sword had come from that very power.
At first, those conjured weapons were weak—even weaker than a demon's claws.But over time, as the demon "nurtured" the weapon, it became stronger—sharper, harder, more deadly.
And the best part?
Blade Hell could absorb special weapons, like Nichirin Blades, enhancing the conjured weapon's properties.
It could even give the new weapon the same demon-killing edge.
Kawanishi had nearly died because of that trick—caught off-guard when Black Fang pulled a weapon from thin air.
But normal iron? It couldn't be absorbed.Only rare, unique weapons worked.
And while the first absorption had the greatest effect, subsequent weapons of the same type added only minor boosts.That's why Black Fang's weapon hadn't become invincible—constant effort was still required.
"So… just be a good blade and turn into an axe, alright?"
(End of chapter.)