Hiru recalled the night his clan was annihilated.
With a mere flick of his wrist, that man had reduced entire rows of houses to rubble, while their people couldn't even lift a hand to resist.
It felt as though something had lodged in Hiru's chest. His throat tightened, and an uncontrollable wave of fear surged up from within.
"Hiru, don't be afraid. I'm here."
Yoriichi drew the long blade from his waist, his expression calm—so calm it bordered on cold. "You're the progenitor of demons, aren't you?"
"Heh... quite the perceptive swordsman." A sneer curled at the corners of the man's lips. "A pity I've lost interest in Breathing Style swordsmen. Otherwise, I might have considered taking you under my command."
Yoriichi's pupils contracted sharply. In an instant, he understood what Hiru feared. His eyes, tinged faintly red, turned icy. "So it was you. You're the one who tempted my brother into becoming a demon."
"Heh... that was your brother? A capable swordsman indeed—he even brought me the head of the Demon Slayer Corps' leader." The man tilted his chin upward, looking down at Yoriichi and Hiru with arrogant amusement. "It seems my generosity that day produced an entertaining result. Heh heh... you must be my descendant, aren't you?"
A chill ran through Hiru's entire body. But alongside that cold, something else rose from deep within—an inexplicable anger. As it flared, the fear vanished like mist.
"Who would ever be the descendant of a worm like you?" Hiru rose to his feet, standing tall on Yoriichi's shoulder. "I'm nothing like you, you cowardly, self-preserving parasite."
Yoriichi's grip tightened around his sword, and the blade instantly glowed a brilliant red. "Hiru, control yourself."
"Mm." Hiru's pupils contracted as he glared at the man, his demon energy roiling. "Brother, what color do you think the progenitor of demons bleeds?"
"You insolent trash." The man's expression twisted into something monstrous as his arms stretched and split into grotesque tentacles. "I won't let you die easily."
Yoriichi dodged the incoming strike, brow furrowed. From the sound alone, he could tell that the attack had severed several trees behind him and stretched far into the distance.
Such terrifying power—any human touched by it would die instantly.
He evaded another sweeping strike, his eyes tracing the man's every move. Slowly, the man's body became transparent in his vision.
But the instant he saw inside it, Yoriichi staggered back in shock. A claw from one of the tentacles grazed him, tearing a piece of his sleeve.
Seven hearts. Five brains.
Impossible.
Stunned, Yoriichi couldn't move. Instead, he continued to observe through his transparent vision—yet his mind unwillingly drifted to the first time he had examined Hiru this way.
Back then, once Hiru no longer suffered from hunger, he had grown a new heart, overcoming the weakness of the neck. After his first full meal, he had developed one brain and two hearts.
Hiru was also... a progenitor of demons.
The thought flashed through Yoriichi's mind. Then, without hesitation, he stopped dodging and charged forward. His crimson blade flared like a blazing sun. In an instant, the man who had held the upper hand moments before was cut apart, his body scattering to the ground.
Yoriichi watched as the man struggled to keep his head from falling, his expression frozen in disbelief and horror.
Hiru stared down at the gushing blood and unconsciously swallowed. The hunger buried deep within him stirred once more, but he stayed still, balanced firmly on Yoriichi's shoulder, glaring down at the man.
"Where is my brother?"
The man's face flushed dark red, his plum-colored eyes locking onto Yoriichi and Hiru with hatred.
"Before that," Yoriichi said quietly, turning to face him directly, "I have something I want to ask. What do you see life as?"
"Looks like his head's too damaged to speak," Hiru muttered. Extending his hand, his gray eyes were cold and detached. "Perfect. I have a new Blood Demon Art I've been wanting to test..."
Yoriichi stepped closer, preparing to deliver the finishing blow. He could see the man's life force still pulsing violently inside him. If that energy manifested as a dangerous Blood Demon Art, it could be disastrous—he couldn't allow Hiru to risk it.
But the moment Yoriichi approached, a cracking sound came from the man's clenched jaw. The next instant, his body exploded violently, sending a storm of blood and flesh fragments scattering in every direction.
Yoriichi swung his blade without hesitation, while Hiru simultaneously released his Blood Demon Art.
Yet in the sudden chaos of the night, even with his heightened senses, Yoriichi only managed to strike down the larger fragments—those bigger than a fingernail.
Hiru knew humans lacked night vision, and even Yoriichi's extraordinary perception couldn't track the smallest bits.
So he focused all his power on the tiniest scraps of flesh, pouring every ounce of energy into his Blood Demon Art.
What he didn't expect was how draining it would be—using the technique on these scattered fragments consumed far more energy than using it on most complete demons.
And instead of contracting, the bloodied bits of flesh swelled, dropping onto the gravel-covered path with faint metallic clinks.
Yoriichi stopped his blade mid-swing, staring blankly, stunned.
"Brother?"
"He got away." Yoriichi lowered his gaze, his tone flat and unreadable. "He split himself into more than eighteen hundred pieces. I only managed to destroy around fifteen hundred. Counting yours..."
"I doubt I even hit two hundred..." Hiru panted lightly. "Using a Blood Demon Art on him drained me more than I expected."
"...Then a piece of flesh about the size of a child's heart must have escaped."
Hiru fell silent.
But then, a voice—filled with rage and despair—pierced the still air.
"So close... just a little more! He actually overcame his weakness—his neck—!"
Hiru and Yoriichi both turned instinctively toward the sound.
The woman who had arrived with the man was kneeling on the ground, screaming. Her voice trembled with grief and fury as she clutched her hair, demon energy erupting violently around her.
"Why won't you die?! Why won't you just die?! That vile man—Muzan Kibutsuji!"
Yoriichi froze at her words. A moment later, the woman's voice faltered. She stared blankly at her hands, her expression filled with confusion.
"I didn't die... Why didn't I die?"
"You said... his name is Muzan Kibutsuji?" Yoriichi approached slowly, crouching down before her. The woman was small, almost fragile. "When I severed his head, you didn't step forward to help him. Instead, I saw hope flicker in your eyes. You wanted me to kill him."
"Of course!" she hissed, gritting her teeth. "That man deserves to die—he deserves to die! Die! Die!!"
Yoriichi simply waited, silent and patient, until her trembling subsided.
When she finally calmed, he spoke softly. "My name is Yoriichi. Tsugikuni Yoriichi. And this is my younger brother, Tsugikuni Hiru."
The woman blinked, her eyes still wet but her voice steadier now. "My name is Tamayo."
Yoriichi glanced toward Hiru perched on his shoulder, then looked back at her.
"Miss Tamayo," he said, voice calm but resolute, "can you tell me more about Muzan Kibutsuji?"