Mount Natagumo, Mid-Slope
"Although I doubt you're that stupid... but judging from your performance, do you really think that just by getting close to me, you can cut off my head?"
Lower Rank Five, Rui, casually threw a punch as if he were playing around, sending the crimson-haired boy flying several meters away. The boy coughed up mouthfuls of blood.
Even so, he forced himself back to his feet, panting heavily, gripping his broken Nichirin Blade, waiting for an opening.
Seeing this, Rui seemed intrigued. He spread his arms.
"Sure. Come on. Try it."
"Ahhh!"
The boy slashed with his sword. Rui dodged left and right like a cat toying with a mouse, striking the boy's face again and again, making him bleed in agony.
Using the momentum from being spun around by the blows, the boy twisted his body and swung—
His blade struck Rui's neck!
Clang!
A crisp metallic sound rang out. The blade failed to leave even the slightest mark.
"See? I told you." Rui's eyes turned vicious as he kicked the boy away. "You're no match for me!"
"My body is tougher than the threads I control. A swordsman of your level can't even cut my threads—yet you think you can cut my neck?"
"Stop dreaming!"
As the boy was kicked away, crashing heavily and raising a cloud of dust, a girl suspended upside down in midair by countless threads let out an unwilling roar. The bamboo muzzle in her mouth muffled it into a low, pained whimper.
"So noisy. Be quiet for a while."
"Your brother belongs to me now. Stop shouting like that."
Slash!
Rui raised his pale arm and clenched his fist toward her. The threads tightened at once, embedding into the girl's body. The sound of flesh tearing echoed as blood sprayed in all directions.
Under such agony, the girl cried out and lost consciousness.
"Nezuko!"
The boy's fury swelled to its limit. The veins on his hand and forehead bulged as if they would burst.
But he clenched his sleeve tightly, forcing down his uncontrollable rage.
"Calm down, Tanjiro. Don't let your emotions take over," he told himself.
"Focus... adjust your breathing..."
"I have to use the strongest form... to end this battle!"
"Total Concentration!"
Tanjiro roared and shot forward. The scar on his forehead twisted grotesquely with his bulging veins.
"Water Breathing, Tenth Form—"
"What are you doing? Don't you understand yet? It's meaningless. Just hand over your sister!"
Rui impatiently flicked out several sturdy threads, intending to erase the boy entirely.
But something unexpected happened.
The threads that had easily sliced through Nichirin Blades before were cut apart as Tanjiro's breathing shifted and his blade began to spin.
It wasn't luck. As Tanjiro's rotation accelerated, Rui realized his threads were being shattered faster and faster.
"Constant Flux!"
With Tanjiro's roar, waves surged along his blade, as if a water dragon had formed from the flowing currents.
The dragon roared, crushing stone and splitting mountains.
The balance of victory seemed to tip.
"Tch... You think that's my limit?"
Rui grew irritated. Crimson demon blood seeped from his hands, coating all his threads.
"That's enough. Goodbye—Blood Demon Art: Cutting Thread Cage!"
Buzz!
A crimson web cage materialized out of thin air, compressing toward Tanjiro with deadly pressure.
He couldn't dodge.
He couldn't cut through it.
The scent was completely different from before.
Tanjiro's heart jolted in shock. His eyes stared blankly ahead.
I'm going to die... I'm going to lose...
But I can't lose...
In that instant, countless memories flashed through his mind.
Until a man's voice echoed within him—
[....Tanjiro, these earrings and the Kagura dance, you must pass them down from generation to generation!]
[....We have a promise.]
Rui, who had been ready to end it, suddenly sensed something change in the boy within his Blood Demon Art.
In less than a fraction of a second, Tanjiro's eyes sharpened. His entire aura turned dangerous.
Hiss!
Scorching air surged from his mouth and nose. The Nichirin Blade in his hand trembled with searing heat.
"...Hinokami Kagura: Clear Blue Sky!!"
The surging Water Breathing form transformed into a crimson flash, as if he had slashed forth a blazing flame.
Rui's pupils contracted. He hadn't expected his Blood Demon Art to be severed by a swordsman who moments ago could barely stand.
Was it luck?
He fired threads again, slicing open the boy's shoulder and neck, cutting across his cheek—but the boy did not retreat.
"Don't stop! Keep running!"
Boom!
With successive spinning slashes, Tanjiro cut through Rui's threads one after another, rapidly closing the distance.
"If I stop now, I'll never be able to move again!"
"I have to fight! I have to protect Nezuko!"
"Ahhh!"
His blade grew faster and fiercer. The boy became a red fire dragon, charging madly between life and death.
"This brat!"
Rui panicked and retreated, continuously releasing blood-infused threads to weave dense traps along Tanjiro's path, trying to strangle him.
The distance shrank. The blade even sliced Rui's clothing, letting him feel the chill of death.
Suddenly, as Tanjiro closed in infinitely, his gaze sharpened. He had found it.
Ignoring everything, he swung his blade, seizing the only chance to behead Rui amid the strangling threads.
"Even if we die together, I'll kill you here!"
Faced with such a desperate charge, even Rui felt a chill down his spine.
What do I do? The blade's coming! No—he'll die first!
My neck is hard. Even if he's gone mad and grown stronger, he can't cut it off instantly!
Kill him now!
Just as Rui steeled himself to kill Tanjiro before the broken Nichirin Blade could reach his neck, he suddenly felt intense heat all around him.
"Blood Demon Art... Exploding Blood!"
Boom!
The demon girl Nezuko, who had been strangled unconscious by the threads, had awakened.
She clenched her fist. The blood that had flowed down along the threads ignited!
In an instant, it burned away all the thread barriers before Rui!
"Impossible! My threads are burned!"
Clang!
Tanjiro burst from the flames like a demon, unharmed. His blade struck Rui's neck heavily.
"The bond between Nezuko and me—no one can sever it!"
Slash!
The broken Nichirin Blade, soaked in the demon girl's burning blood, sliced through Lower Rank Five's head like tearing cloth.
...At the same time, Asuka had already arrived.
From afar, he saw the crimson blade cleave through flesh, saw the terrifying demon's head soar high into the air.
"What a powerful sword form..."
Asuka felt a thought stir within him.
This was a power worth learning.