The battle on Narrow Isle raged on.
Dōma, Hantengu, and Kaigaku continued to restrain Tsugikuni Michikatsu, while Kibutsuji Muzan focused on regenerating the brain that Michikatsu had destroyed.
Though Michikatsu's Sun Breathing could not compare to Yoriichi's, its flames still managed to suppress Muzan's regeneration. It would take some time before he could completely heal.
But Michikatsu himself was nearing his limit. After performing only four forms of the Sun Breathing, he was already almost completely exhausted.
At this moment, the Sun Breathing was a double-edged sword for him. Even if he switched to the Breath of the Moon, the forms he used would still be enveloped by Sun flames—because this power was not truly his own. He could not control it freely.
Dōma covered half of his face with one fan, smiling mockingly.
"Looks like I'll be the next Upper Rank One, won't I? Kokushibō-san, I really have to thank you for this."
Kaigaku's eyes glimmered with greed. If the hierarchy of the Upper Moons shifted again, his position as Upper Rank Five could advance to Four—and with that, he'd gain more of Muzan's blood, and his strength would increase.
With no room to retreat, Michikatsu resolved to fight to the very end.
"Breath of Thunder, Sixth Form: Rumble and Flash!"
Eager to seize the moment, Kaigaku launched the first attack. Lightning-shaped slashes erupted outward from his body, striking toward Michikatsu.
"Breath of the Sun, Ninth Form: Radiant Beneficence!"
The searing solar flames along Michikatsu's crimson blade burned away every trace of Kaigaku's lightning. In the same instant, he swung down in a spiraling slash.
Kaigaku's right arm was severed in a flash, and the stump ignited—flames continued to burn fiercely along the wound.
He stared at his arm in terror. The fire would not go out—it was spreading across his body.
"Cut off the flesh where the flames touched!" Hantengu shouted.
Snapping back to his senses, Kaigaku hastily sliced away the burning flesh—but his arm refused to regenerate.
Deprived of his sword arm, Kaigaku could barely fight. Seeing this, both Dōma and Hantengu dared not let Michikatsu's crimson blade touch them. They switched to long-range attacks.
"Blood Demon Art: Lotus-Bodhisattva Ice Statue!"
Dōma conjured two enormous ice lotuses in the shape of young maidens. From their mouths, they breathed freezing mist, spreading rapidly toward Michikatsu.
"Blood Demon Art: Wood Dragon Gale!"
Hantengu's clone, Zohakuten, summoned a massive wooden dragon that spewed violent wind from its maw, combining with Dōma's freezing mist to drive it straight toward Michikatsu.
"Breath of the Sun, Fifth Form: Solar Radiance Thrust – Calamity!"
It was a form Michikatsu had just created—modeled after the Breath of the Moon, Fourteenth Form: Catastrophe, Tenman Crescent Moons.
It generated countless burning crescent blades, and as he charged forward, a roaring tornado of fire spiraled around him.
When the firestorm collided with Dōma's frost, explosions boomed through the air from the violent difference in temperature.
Moments later, the fire devoured the cold mist entirely, and Michikatsu's thrust followed through.
Zohakuten was cleaved cleanly in two.
Dōma's twin fans shattered, and a deep gash split open across his chest.
In an instant, all three Upper Moons present had lost their fighting ability.
But Michikatsu was in no better shape. The repeated use of Sun Breathing had pushed his body past its limits—the flames had begun to consume him. His left arm had already started to carbonize.
Through the Transparent World, he could see his own condition clearly. He knew that if he performed one more Sun Breathing form, he would lose all strength and fall. He could not waste his remaining power on Dōma and the others.
Meanwhile, Muzan, who had been watching from a distance, had already regenerated the brain Michikatsu destroyed.
Losing one brain had barely affected Muzan's power—but he had no desire to experience such danger again. Even if Michikatsu's flames were weaker than Yoriichi's, he refused to take any chances.
To Muzan, the Twelve Kizuki were mere tools—disposable at any moment. Their only value was in how well they served his purpose.
The grip on Michikatsu's sword weakened, and the blade lost its crimson glow. The flames on his body dimmed.
Muzan sneered.
"I don't know how you managed to wield the Breath of the Sun, but it seems to rely on some external force, doesn't it?"
"Yoriichi is dead. And soon, you'll join him. The only one left who knows the Sun Breathing now is that boy—Kamado Tanjiro, was it?"
"Once I kill him, the legacy of the Sun Breathing will vanish completely. Then no one will be left who can oppose me."
"The Demon Slayer Corps and Ubuyashiki Yōsuke are powerless. That man dreams of dying together with me—I won't grant him that satisfaction."
"Once I become the ultimate lifeform, I'll hunt them all down, one by one. You were once my most capable subordinate, Kokushibō. Consider this mercy—soon, they'll all follow you to hell."
Kamado Tanjiro.
Michikatsu had heard the name before, but he had never met him.
Hearing that this boy had inherited the Sun Breathing, his heart grew calm.
Now, only one thought filled Michikatsu's mind:
As long as the Breath of the Sun will not perish… that is enough. I have never met him, but I believe—the child chosen by Yoriichi will carry on his will, and realize the world Yoriichi once dreamed of.
Michikatsu gripped his blade tightly, his gaze unwavering as he faced Muzan.
"The Breath of the Sun will never be extinguished. Because it is more than just a technique—it is a spirit. The will to eradicate all demons from this world!"
"Breath of the Sun, Twelfth Form: Flame Dance!"
Dragging his battered, burning body, Michikatsu swung with unyielding resolve—two flaming arcs cleaving toward Muzan.
But his body was already spent. The form he unleashed lacked power, its speed faint compared to before.
Muzan's hands morphed into piercing whips that shot forward, impaling Michikatsu's body and breaking his form mid-swing.
Michikatsu collapsed to the ground, his flames dying out. His body continued to carbonize; it would not be long before he turned completely to ash.
As Muzan raised his arm to finish him off, he suddenly sensed an aura approaching—one identical to his own.
He looked down at Michikatsu's half-charred body and smiled coldly.
"Ubuyashiki Yōsuke… you're too late. By the time you arrive, there will be nothing left but a pile of cinders."
Before him, a wooden door materialized. Dōma, Hantengu, Kaigaku, and the imprisoned clergy family vanished into it, disappearing from Narrow Isle.