Chapter 3: The First Demon Battle: The Timeline Diverges
Kanami woke to the feeling of fresh snow being brushed off his face. The events with Tomioka Giyu and the immediate fallout had been a terrifying blur. Tanjiro, having successfully pleaded for his sister's life, now regarded Kanami, the bizarre man who had appeared out of thin air, with cautious gratitude. The sun was beginning to set, staining the western horizon in shades of crimson and violet.
"We need to find shelter," Tanjiro said, his voice raw but determined. "It's not safe for Nezuko out here when it's dark."
"Right," Kanami rasped, his throat still dry from shock and yesterday's liquor. He reluctantly helped Tanjiro drag a few fallen logs near a rocky outcrop, creating a makeshift, pathetic camp. Tanjiro was clutching his broken axe, his grief palpable but contained.
The moment the last sliver of the sun vanished, the air changed. It became heavy, oppressive, and then, it was choked by a grotesque, rotten stench—a smell that was thick with malice and decay. Tanjiro immediately stiffened, his hand finding the grip of his axe.
Kanami's mind, however, was racing in outright panic. This is wrong! The first demon Tanjiro fights is supposed to be a simple, solitary brute in a temple, miles from here! What is this massive demon scent?
The odor intensified, pulling him from his timeline-obsessed thoughts. He realized with a terrifying jolt: his very presence, the disruption of that critical, initial scene with Tomioka, had already shattered the established narrative. The world of Kimetsu no Yaiba was bending and warping around him.
A rustling in the dense, dark woods preceded their arrival. Six lesser demons—low-grade, hunched creatures with yellowed eyes and clawed hands—emerged, their forms indistinct in the deepening gloom. But they were only a distraction. Behind them, a figure of tremendous size and menace stepped into the clearing. It stood easily twice the height of Tanjiro, its skin a sickening, pale grey, its frame heavy with muscle and strange, bony growths.
Kanami's Devouring Blade
"Get behind me, Tanjiro!" Kanami yelled, the instinct to protect the protagonist overriding his fear. He reached down and drew his blade—the Strongest Nichirin Sword that had inexplicably appeared at his hip.
He was forced to fight immediately. There was no time for thought, only the panicked reliance on the raw, intrinsic power of his Otherworldly Swordsmanship. He brought the blade up in a clumsy, hacking motion. The sword instantly reacted, its silvery metal turning a murky, bruised purple, radiating a visible, consuming hunger.
The lack of formal training was immediately obvious. He moved like an amateur, his footwork sloppy, his guard too low. He struggled against the first creature, its claws scraping shallowly across his left shoulder before he managed a desperate, final swing that decapitated it.
As the demon dissolved into ash, a plume of thick, dark, smoky mist was drawn violently, visibly, into the dark purple blade. The sensation that followed was instantaneous and brutal, yet exhilarating.
> SYSTEM: Blood Devoured. User Strength +5%. Hair Color transforming to Red. Right Eye Color transforming to Yellow.
>
A savage surge of energy exploded within him, driving the fear back and replacing it with raw, aggressive power. His jet-black hair flared, the roots rapidly turning a vibrant, alarming red, and his right eye pulsed, glowing a predatory, molten yellow, like the eye of a dragon.
With this newfound, fueled power, Kanami dispatched the next four lesser demons quickly, moving with an aggressive speed he didn't know he possessed. Meanwhile, Tanjiro, recovering from his shock, saved the day against the sixth and final lesser demon by hooking its neck with his axe and dragging it with desperate strength into the first weak rays of the ascending moon, where it screeched and crumbled.
The Modified Breathing and The Merge
As the last lesser demon dissolved into ash, a clear, high-pitched digital "DING!" echoed only in the confines of Kanami's mind.
> SYSTEM (Reward): Mission Complete. Modified Breathing Technique (Unlocked).
> SYSTEM (Prompt): User has acquired Modified Breathing Technique. Would the user like to Merge this technique with Otherworldly Swordsmanship (Blood Devour)? (Y/N)
>
Kanami didn't hesitate. Yes! he screamed mentally, recognizing this was his chance to gain the structured power necessary to survive this nightmarish reality.
> SYSTEM: Merge Complete. Heavenly Demonic Devouring Breathing Style acquired. 14 Forms available. 2 Forms unlocked.
>
| Heavenly Demonic Devouring Forms |
|---|
| Form 1 (Unlocked): Devouring Gale - First Fang |
| Form 2 (Unlocked): Crimson Soul - Blood Feast |
| Form 3 (Locked): Soul Cleansing Veil (Cost: 20 DP) |
| ...The remaining eleven forms remain locked... |
Final Battle: The Bone Demon
Before Kanami could savor the power or even register the details, the final, stronger demon, Hakkotsu, the Bone Demon, stepped forward, its massive form eclipsing the moonlight.
"You smell of death, yet you glow with power," the demon sneered, its voice a gravelly rumble. "And that sword... it sings for blood. I shall be the one to devour you!"
Kanami instinctively shoved Tanjiro, who was still only armed with his broken axe, behind him. He took a deep, controlled breath, instantly channeling the Heavenly Demonic Devouring Breathing. The raw, kinetic energy of the breathing technique flowed, mingling with the dark, devouring essence of his blade.
"Why is there a stronger demon here?" Kanami thought frantically. "The story changed. This isn't canon anymore. I can't rely on the plot. I have to win this now!"
Kanami lunged, executing his first new move with desperate precision: Heavenly Demonic Devouring Breathing, Form 1: Devouring Gale - First Fang!
He delivered a powerful, twisting horizontal sweep that cut deep into Hakkotsu's thick, gray body. The Devouring Essence instantly tore away the flesh and blood, dissolving it and giving Kanami an explosive burst of speed that propelled him out of the demon's reach.
The Bone Demon roared in pain and surprise, retaliating with its Blood Demon Art: Bone Spike Barrage! Hardened, razor-sharp spikes shot from its body like quills.
Kanami was ready. He spun his body, instantly channeling his second form to deflect the barrage and counter-attack. Heavenly Demonic Devouring Breathing, Form 2: Crimson Soul - Blood Feast!
He unleashed a rapid, blurring circular chain of slashes. Each shallow hit drew a thin line of blood, and the blade instantly devoured it, giving him successive, compounding bursts of acceleration. The demon couldn't regenerate fast enough to keep up with the overwhelming speed and sheer volume of the attacks. Finally, with a decisive surge fueled by the consumed blood, Kanami drove his blade through the Bone Demon's neck, severing the head cleanly.
Kanami stood over the dissolving ashes, panting, the strange, demonic-like power receding from his body. His hair began to fade back to its natural black, and the yellow glow in his right eye subsided. The immediate, terrifying threat was gone, but a terrifying new reality had set in: The story was no longer his guide. He was alone, armed with unstable, demonic power, on a timeline that was already spinning out of control.
Kanami has saved Tanjiro and Nezuko from a premature and dangerous encounter, but at the cost of changing the story completely.