Time flew by.
All members of the Demon Slayer Corps were training under tense and pressing conditions.
Yōsuke, too, was not idle. He sought out Kokushibō's younger twin, Yoriichi Tsugikuni, and requested to learn the Breath of the Sun.
Yoriichi did not withhold knowledge because Yōsuke was a demon. Instead, he gladly accepted and poured all he knew of the Breath of the Sun into his teachings.
Yet when Yōsuke attempted to perform it on his own, his entire body felt as though his meridians were being scorched and melted by the sun's fire. Agonizing pain consumed him.
Terror struck him—because as he invoked the Breath of the Sun, he felt the presence of death itself. His instincts screamed: if he continued training in this art, he would certainly die.
But when Yōsuke practiced other Breathing Styles, the techniques flowed smoothly—yet their power was pitiful, barely a fraction of the Breath of the Sun. They offered almost nothing in terms of improving his combat ability.
In frustration, Yōsuke summoned the system he had long ignored and demanded to know why he could not learn the Breath of the Sun.
Ding. Host, please value your life. The Breath of the Sun mimics the power of the sun. The sun is your weakness. To train in it is no different from suicide.
The realization that the strongest Breathing Style in the world was forever beyond his reach left Yōsuke filled with bitter regret. Even if the system granted him other Breathing Styles, none were the Breath of the Sun, and thus they offered him no true strength.
Ding. System reminder: if the host is unsatisfied with the Breathing Styles provided, he may, through his own effort, derive a new style from the Breath of the Sun, suited to himself. The system is only an aid—it does not mean the host must rely upon it completely.
Those words rekindled hope within Yōsuke.
The system was right. If he could not learn the Breath of the Sun, and if the other styles were too weak for him, then why not create one of his own?
Even Kokushibō had forged his own Breath of the Moon. There was no reason Yōsuke could not do the same.
Thus, Yōsuke began training to forge a Breathing Style uniquely his own.
The other Hashira, seeing his tireless effort, pushed themselves even harder to avoid being left behind.
Even Tamayo, determined to be useful in the final battle, began researching poisons designed specifically to kill demons.
Within the small confines of the Ubuyashiki estate, an atmosphere of fierce competition and mutual drive was born.
A month passed—no more than the blink of an eye to Yōsuke.
One night, the Wind Hashira, Kentō Kamiji, who had always regarded Yōsuke as a thorn in his side, sought him out.
Though Kentō no longer drew his blade at every provocation, his face showed nothing but hostility.
With a challenging glare, Kentō sneered:
"Judging by your look, you're trying to create a derivative of the Breath of the Sun, aren't you? What's wrong—want to test it out in a duel?"
Yōsuke, who by then had already grasped the faint outline of his new style, naturally would not turn down the challenge. He accepted at once.
Kentō's eyes gleamed with violent intent as he slowly drew his Nichirin Blade.
"If you die in this match, don't blame me!"
Yōsuke smirked with disdain.
"If you can manage it, then by all means—try."
Kentō gripped his blade with both hands. The pale green steel slowly turned red.
Yōsuke chuckled. So that was why Kentō had come—he had awakened the Crimson Blade.
But to ignite a blade through sheer grip strength? That was something Yōsuke himself could do with ease.
He, too, drew his Nichirin Blade—and with a surge of power, the steel glowed crimson.
"Wind Breathing, First Form: Dust Whirlwind Cutter!"
Kentō launched first, closing the distance in an instant. His blade spun with slicing gales powerful enough to tear apart the ground as it thrust toward Yōsuke.
Yōsuke raised his blade horizontally before his chest. Kentō's sword tip met his with a clash, and the violent winds howled, whipping the courtyard into chaos.
The commotion quickly drew the attention of the other Hashira in training nearby.
"What's going on? Why are Kentō and Yōsuke-sama fighting?!"
Water Hashira Eriko Tokimoto asked Thunder Hashira Raihui Sayaka in confusion.
"I didn't arrive much earlier than you, so I'm not sure either," Raihui replied, though his eyes never left the battlefield.
"I think they're sparring," said Flame Hashira Shinzuka Sho Rengoku, arms folded. Sensitive to the flow of intent, he noticed, "Neither of them is giving off killing intent."
Eriko nodded. "I see. Then… who do you think will win?"
"Yōsuke Ubuyashiki." ×3
"What? Not one of you thinks Kendō will win?"
Stone Hashira Daigo Shimazawa explained firmly:
"Though it looks like Kentō is pressing Yōsuke-sama, if you look closely, Yōsuke-sama is only using basic swordsmanship. He hasn't drawn on any of his other powers, and yet he's fending Kentō off with ease. Kentō's defeat is only a matter of time."
The view shifted back to the duel.
"Wind Breathing, Eighth Form: Primary Gale Slash!"
Kentō surged forward, striking at Yōsuke head-on. When Yōsuke blocked, Kentō spun around him like a cyclone, slashing from all sides, whipping up spiraling blades of wind.
But Yōsuke's sharpened dynamic vision pierced through his assault. He drove his Nichirin Blade into the ground, anchoring himself and withstanding the whirling storm.
The impact forced him back several steps, gouging a deep scar into the earth with his blade.
Panting heavily, Kentō's stamina was waning. Repeated use of Wind Breathing combined with the Crimson Blade had drained him.
He knew he wasn't Yōsuke's equal—but Yōsuke's refusal to go on the offensive felt like mockery.
"Are you toying with me?! Why won't you attack? Where are your other powers as the so-called Demon King? Do you think I'm not worth it? Don't you dare look down on me, you bastard!"
At that moment, Yōsuke closed his eyes.
Through his clash with Kentō, a powerful spark of inspiration ignited within him. He had finally grasped the shape of his own Breathing Style.
When he opened his eyes again, he smiled faintly at Kentō, who stood trembling with frustration.
"I should thank you. Because of you, I've forged a Breathing Style of my own. Now—it's my turn to strike. Remember… don't die."
Kendō steadied his breath, his body tensed, ready to face whatever came.
"Blood Breathing – First Form: Crimson Decay!"
Yōsuke slowly rose into the air. Around him bloomed an enormous, blood-red flower, enclosing him within its petals.
Kentō's instincts screamed at him to flee. His very soul warned: If you stay, you will die.
But his pride as a Hashira would not allow him to retreat. At the very least—he would take this attack head-on!
"Wind Breathing, Ninth Form: Idaten Typhoon!"
Kentō's body spun into a furious whirlwind, circling the massive crimson flower, slashing it again and again, hurling countless blades of wind into its petals.
Yet his strikes vanished into it like stones into the sea—without so much as a ripple.
From within the blood-red blossom came Yōsuke's voice.
"Bloom, crimson flower."
The petals unfurled, scattering into countless shards of scarlet light. Then, like a storm of bombs erupting, they exploded outward in a shockwave that shook the entire courtyard.
Grotesque—yet breathtakingly beautiful.
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