Rui, the "youngest son" of the Spider Family, was in truth its tyrant and puppeteer.
There was no real bloodline among them—every "family member" was a captive forced into their roles to appease his warped obsession.
No matter what happens, parents must protect their children. Older siblings must protect the younger ones—even at the cost of their lives.
That was Rui's creed. His delusion.
Now, those "family members" stood before Tanjiro and Zenitsu, ready to kill in Rui's name.
Tanjiro exhaled slowly, entering Total Concentration Breathing. The Nichirin Blade in his hands gleamed faintly beneath the moonlight.
Spider Father.
Spider Brother.
Spider Sister.
Each advanced to attack.
Spider Father moved first. His massive, monstrous frame lunged forward with a single swing of his arm—a blow strong enough to pulverize a tree trunk.
BOOM!
"Tanjiro!" Zenitsu screamed. He was sure the boy had been smashed into pulp.
But as the dust cleared, reality defied expectation.
Tanjiro still stood, blade raised high, the impact absorbed cleanly through his breathing technique. The strike hadn't even shaken him.
Zenitsu's eyes widened. He finally understood just how deep Tanjiro's mastery of the Water Breathing technique ran—its precision strengthened even the steel of his sword.
Spider Sister shrieked in fury. Her "father" had failed, so she charged in from behind, claws ready to sever Tanjiro's head.
But before she could strike—
BAM!
The wooden box on Tanjiro's back burst open.
A small figure shot out like a cannonball and slammed a flying kick into Spider Sister's stomach.
She gagged, spit spraying as her body crumpled backward.
The "beast" landed gracefully—Nezuko, already replacing the bamboo muzzle between her lips out of habit and discipline. Even in battle, she kept her promise to Master Urokodaki: never bare her fangs in front of others.
Zenitsu froze mid-gasp.
Then his soul nearly left his body.
Too cute… way too cute…
Though she resembled Chika in face, Nezuko's aura was different—gentle, pure, radiant. Zenitsu swore he could hear the arrow of Cupid pierce his heart.
His hypersensitive hearing had already told him there was something alive inside Tanjiro's box—a heartbeat faint yet steady. He had suspected it was a demon.
But a demon like this? He couldn't have imagined it.
While Zenitsu stood lovestruck, Spider Brother crept up behind him, aiming to eliminate the weakest link first.
Catch the softest target—always the best tactic.
"Got you!"
"Mm-mm!" Nezuko barked a muffled warning through her bamboo gag and lunged again.
This time, she drew a short wooden training sword—not even a real blade.
Water Breathing, First Form: Water Surface Slash!
The swing was clumsy, uneven—but genuine.
Her raw strength made up for what she lacked in form. The strike tore open a long, deep gash across Spider Brother's torso.
Had that blow landed on his neck, he might have been beheaded right then.
A sword-wielding demon.
A demon who could use Breathing Techniques.
And an even scarier older sister waiting somewhere nearby.
Zenitsu's head spun. What kind of group did I get dragged into?!
If Chika had been there, she'd have crossed her arms and muttered,
"Kid, just wait. You'll meet a gun-toting demon hunter, a monk with meteor hammers, and a pink-haired girl whose muscles are eight times denser than yours…"
Back to the battlefield:
Tanjiro and Nezuko stood back-to-back, both alert, breathing steady. Nezuko wanted to brag about using her first proper Breathing strike, but there was no time for celebration.
The remaining demons circled, snarling.
Meanwhile, at the Demon Slayer Corps Headquarters
"Giyu, Shinobu—this mission's yours."
"Understood."
At the Master's command, two of the Corps' strongest warriors prepared to depart for Mount Natagumo.
The Water Hashira, Giyu Tomioka—the prodigy who created the Eleventh Form of Water Breathing.
The Insect Hashira, Shinobu Kocho—the poison master whose toxins could kill even Lower Moons.
Reports claimed a Twelve Kizuki had appeared on the mountain.
If they didn't hurry, they might arrive to find nothing left but corpses—or, if Chika had her way, a completely demon-free zone.
On the mountain, Tanjiro's group fought fiercely.
Elsewhere, Chika's duel with Rui had reached its climax.
Though she hadn't invoked the Hinokami Kagura, she was dominating the Lower Moon with pure Water Breathing.
Her Beast Instinct guided her body, dodging every fatal thread. The minor cuts she ignored—they'd heal in seconds anyway.
That relentless drive unnerved even a demon.
Rui attacked with everything he had, his highest-grade threads slicing through the air, but with each step, he retreated.
Several times, Chika's blue Nichirin Blade passed within a breath of his neck.
"You… what are you?!" Rui roared, trembling with fury and fear. "Are you even human?!"
Chika said nothing.
Her expression was cold—serene, even.
Every motion of her sword promised death.
The outcome wasn't decided yet.
But it was clear to everyone watching—
It was only a matter of time.