Inside the Infinity Castle, Shinichi and Shōkyū's battle had already been going on for a long time.
Bluish-green blade light and dark-red thorn whips collided again and again, each clash bursting into a ring of air waves.
More wounds had appeared on Shinichi's body, and fresh blood soaked into the hilt of his sword.
Yet Shōkyū, standing across from him, still showed no signs of exhaustion.
Even when Shinichi's blade light cut open his body, the wounds only rippled for a moment like the surface of water before quickly vanishing.
"What's wrong? Starting to run out of stamina?" Shōkyū looked at Shinichi, his crimson eyes full of mockery.
"I thought you'd last a little longer than this. Come on! Keep going! Let me see how many more times you can swing that sword!"
"Don't worry. Before I lose the strength to swing it, I'll make sure to send you back to that precious Yomi you care so much about."
Shinichi smiled fiercely and raised his Nichirin blade, answering Shōkyū with a swift slash.
But the attack only cut through two thorn whips.
Shinichi knew Shōkyū was trying to wear down his stamina.
At the same time, he was also wearing down Shōkyū's power.
Every slash carried the force of life into Shōkyū's body, eroding the power of Yomi within him.
The effect was tiny, almost negligible, but as long as it continued to build up, there would eventually be a moment when quantity became quality.
...
Meanwhile, on a nearby battlefield, a streak of purple light suddenly rushed in from the edge of the fight.
"Insect Breathing, Dance of the Bee Sting: True Flutter!"
The slender Nichirin blade pierced forward like a venomous bee's stinger.
A demon had just tackled a Demon Slayer to the ground and was opening its fangs wide, but the instant it lowered its head, the sharp tip of the blade pierced through its neck.
An eerie purple spread across the demon's throat at once.
Then—Bang!
The brutal demon collapsed heavily to the ground.
The Demon Slayer who had been knocked down was still shaken, but when he saw the figure standing behind the fallen demon, his eyes lit up.
"Insect Hashira!"
"Be careful, okay?"
Shinobu Kocho smiled as she reached out and pulled the Demon Slayer to his feet.
Then she stood on tiptoe and patted his shoulder before spinning the slender Nichirin blade in her hand and rushing toward the endless swarm of demons under the young swordsman's admiring gaze.
"Sorry, everyone. We're a little late."
Her beautiful violet eyes turned toward the two figures locked in battle not far away.
"Now, let me see who's causing so much trouble."
And Shinobu was not the only one joining the battlefield.
More figures were already pouring in.
"Flower Breathing, Third Form: Honorable Shadow Plum!"
Pink blade light bloomed like plum blossoms, layer after layer slashing toward more than a dozen demons. Kanae Kocho's figure flickered within the blade light.
Her steps were slightly unsteady, but every slash was still precise and graceful.
"Wind Breathing, Fifth Form: Cold Mountain Wind!"
Emerald-green blade light swept through like an autumn gale scattering fallen leaves, shredding all the low-level demons rushing toward Kanae.
Sanemi Shinazugawa arrived beside her with his sword in hand.
"Don't push yourself too hard."
Kanae smiled gently.
"I'm all right, Sanemi-san."
"Flame Breathing, Fourth Form: Blooming Flame Undulation!"
Orange-red flame-like blade light spun out, directly grinding a huge demon into ash.
Kyojuro Rengoku gripped his Nichirin blade tightly. His breastbone was still aching faintly, but his laughter remained as loud as ever.
"Umu! Good thing we're not too late!"
"Namu Amida Butsu…"
A low Buddhist prayer sounded.
Gyomei Himejima's towering body descended like a god.
His Nichirin spiked flail and great axe smashed down together, charging into the demon horde like a war chariot and stirring up a storm of blood and gore.
"Serpent Breathing, Second Form: Venom Fangs of the Narrow Head!"
A winding blade light stabbed out from the shadows like a venomous snake, accurately cutting down two demons that had been lurking behind Tengen Uzui.
Tengen immediately shouted his thanks to Obanai Iguro.
"Thanks, Obanai!"
"Love Breathing, First Form: Shivers of First Love!"
Mitsuri Kanroji's small face was twisted slightly in pain, and thick bandages were still wrapped around her abdomen. But a little pain was not enough to make her back down.
Besides—
'Obanai-san is working so hard. I can't fall behind either!'
"Mist Breathing, Third Form: Scattering Mist Splash!"
"Maple Breathing, Fourth Form: Autumn Fire-Dyed Dance!"
Pale-blue blade light spread like morning mist, followed closely by more crimson maple-leaf sword light.
Together, they cut down every demon blocking the path.
The Tokito brothers moved one ahead and one behind, their coordination flawless.
Yuichiro's expression was excited, while Muichiro remained calm and steady, yet the two of them worked together with perfect harmony.
"Water Breathing, Sixth Form: Whirlpool!"
Water-blue blade light slashed in from Giyu Tomioka's side.
Sabito stood back-to-back with Giyu.
"I knew you'd be fine."
The Hashira-level swordsmen of the Demon Slayer Corps had all arrived!
Shōkyū noticed it as well.
A shadow passed through his crimson eyes, and a trace of irritation rose in his heart.
Humans really were disgusting creatures.
"Hmph…"
Shōkyū let out a cold laugh.
"So a few stronger insects have arrived? What difference does it make? You're still here to die!"
"To die?"
Shinichi wiped the blood from the corner of his mouth and grinned.
"No. We're here to send you off."
"You really do have a stubborn mouth. Let's see how much longer you can keep talking!"
The thorn whips surged violently.
At the same time, an even more horrifying change began to happen.
Shōkyū's body started swelling at terrifying speed.
Huge masses of flesh bulged out across him, forcing his body to grow into a massive flesh giant six or seven meters tall.
Faced with this sight, Shinichi tightened his grip on his sword, showing no intention of retreating. Milky-white and bluish-green blade light flared at once.
Across the battlefield, the appearance of the Hashira had greatly boosted the morale of the Demon Slayers.
In that moment, every member of the Corps found something to rally around.
They moved toward the Hashira one after another, cutting down the demons with all their strength.
"Kill them!!!"
"For the Master! For the Demon Slayer Corps!"
Their cries echoed through the Infinity Castle.
Shinobu Kocho's figure weaved through the demon horde, her thin blade moving as fast as lightning.
Every thrust pierced a demon's head with perfect accuracy.
Kanae Kocho and Sanemi Shinazugawa guarded each other.
The blade light of Flower Breathing formed a gentle barrier, stopping the demons that tried to approach one after another, while Wind Breathing carried the most violent killing intent and tore every demon apart.
Kyojuro Rengoku's Flame Breathing burned in the darkness like a blazing sun.
Orange-red blade light incinerated every demon around him, and his laughter rang across the battlefield.
"Burn! This is what a battle of the Demon Slayer Corps should be!"
Gyomei Himejima's presence was even more of a nightmare for the demons. Every swing of his Nichirin spiked flail and great axe cleared out a huge area.
Before him, "brutal" was no longer a word suited to describing demons.
It suited him far better!
Tengen Uzui, Obanai, and Mitsuri also worked together smoothly, their blade lights crossing as they cut down demon after demon.
The Tokito brothers fought side by side, Maple Breathing and Mist Breathing complementing each other.
Red and blue blade lights flickered in the darkness.
Yuichiro looked excited, while Muichiro looked composed, but their coordination was flawless.
Giyu Tomioka and Sabito fought together.
Giyu had already consumed a great deal of stamina, and Sabito's injuries had not fully healed either, but none of that affected the perfect cooperation of their Water Breathing.
The bluish-green Nichirin blade cut through thorn whip after thorn whip.
But against Shōkyū, who had transformed into a massive flesh giant, such losses meant almost nothing.
He roared and smashed down with one fist.
Boom!
The ground beneath Shinichi's feet was instantly blasted into a pit half a meter deep.
"Terrifying strength, sure. But Shōkyū, I can feel it. You're afraid, aren't you? You're so scared you've hidden yourself inside a shell of flesh!"
Shinichi swung his sword, his black eyes reflecting that huge, terrifying head, hideous as an Asura.
Shōkyū, now transformed into a flesh giant, seemed unable to speak.
But he opened his enormous mouth, wide enough to swallow a whole person, and let out a roar that shook the battlefield.
The killing intent in his crimson eyes was almost solid enough to take form.