The old man's warning to Yosuke and the others added an unsettling layer of mystery to Hachijō Island.
The cold night wind howled. Iguro Obanai's expression was grim. The old man's description of the "serpent god" devouring live sacrifices overlapped eerily with the image in Obanai's mind—of that serpent demon who once fed on infants.
A thought began to gnaw at him.
Could it be... that the serpent demon from back then hadn't truly died?
"Crunch… crunch…"
A chewing sound came from nearby.
Kanroji Mitsuri was holding a bag of sakura mochi, eating with small, delighted bites.
Noticing Obanai and Yosuke's gaze, she blushed and said sheepishly,
"I got a little hungry… Do you guys want some?"
"We're fine. You go ahead and eat."
Obanai's tone was calm, but his mismatched eyes betrayed a faint, unguarded warmth.
"Hissss…"
Kaburamaru, the white snake coiled around Obanai's neck, flicked its tongue rapidly, producing a series of tense hissing sounds.
"What's wrong with Kaburamaru?" Mitsuri asked curiously.
Obanai's heterochromatic eyes narrowed, staring into the depths of Hachijō Island.
"Kaburamaru's senses are sharp. It's detected another of its kind nearby… and this one isn't ordinary. I'd bet it's the so-called 'serpent god' that old man spoke of."
To uncover whether the serpent god was truly that serpent demon from the past, and to learn more about the shrine family's fate, the three of them once again ventured deep into Hachijō Island.
After pushing through a dense and tangled forest, they finally arrived at the ruins of what was once the Iguro family estate.
Though the buildings were now in decay, traces of their former luxury could still be seen.
Yosuke wrinkled his nose. A foul, fishy stench hung in the air—mixed with the unmistakable aura of a demon.
His sharp eyes lit with realization.
"So that's it… The smell of snakes was used to mask the scent of a demon. That's why we couldn't sense it when we first arrived on the island."
As they stepped into the derelict compound, a massive crawling sound echoed from the surrounding structures—something large was moving swiftly toward them.
Obanai and Mitsuri immediately took defensive stances, but Yousuke remained composed. From its aura alone, he could tell: this demon was weak—not even a member of the Twelve Kizuki.
Suddenly, a monstrous figure burst forth—its upper body human, its lower body serpentine—screeching in fury.
Obanai froze, disbelief washing over his face. As the Serpent Hashira, he instantly recognized the creature before him.
The serpent demon's eyes widened as well.
"Iguro Obanai! I knew it—I knew you'd come back to Hachijō Island!"
"Eh? You two know each other?" Mitsuri asked, bewildered.
But Obanai didn't answer. Every ounce of his attention was fixed on the demon before him.
His voice was low, trembling with restrained emotion.
"Iguro Maharu… Why? Why did you become a demon?"
The serpent demon glared at him, her voice dripping with hatred.
"All of this—everything—is your fault, Obanai! Because of you, the Iguro clan was annihilated! I wanted revenge… so I devoured the flesh and blood of the Serpent Mother—and took her place as a god!"
Obanai fell silent. Memories—dark and suffocating—flooded his mind.
Mitsuri looked completely lost.
"W-what's going on? Obanai-san…"
Yousuke extended an arm, stopping her.
"Don't ask, Mitsuri. Let him handle this."
The serpent demon's laugh was sharp and venomous.
"So this is what became of you—you joined the Demon Slayer Corps, a dog of the humans! Once a sacrifice yourself… very well, then. Allow me to offer your flesh to the Serpent Mother in your stead. I'll devour you piece by piece!"
Obanai's tone darkened.
"I've never forgotten that I'm one of the Iguro clan—the vile, twisted Iguro clan that slaughtered innocents and treated human lives as playthings. What befell you all was nothing but retribution!"
"Such self-righteous words," the serpent demon sneered.
"You think wrapping bandages around your face can erase your lineage? The scar beneath them will always remind you of what you are—an Iguro! You can never escape that!"
The serpent demon slithered rapidly through the ruins, striking at Obanai again and again. But Obanai made no move to counterattack—only to evade.
Mitsuri grew anxious.
"What is Obanai-san doing? That demon's so weak—he could've killed it in one strike!"
Yosuke shook his head.
"He's fighting something else right now—not the demon, but himself. Believe in him. He'll find his answer."
Obanai's movements were fluid—serpentine. He slipped between attacks with effortless grace, each motion deliberate, controlled.
Rain began to fall, pattering softly over the ruins.
Frustrated by her missed strikes, the serpent demon opened her jaws wide, spewing a torrent of dark violet venom straight at him.
"Serpent Breathing, First Form: Winding Slash!"
Obanai spun counterclockwise, evading the venom as his blade curved through the air in a serpentine arc. The slash sliced clean through the serpent demon's tail.
Her agonized scream echoed across the entire island.
Writhing on the ground, she glared up at Obanai with venomous hatred.
"What now? Will you kill me too? Go ahead! You've already taken the lives of over fifty members of our clan—what's one more?"
Obanai's grip on his Nichirin blade trembled slightly.
"Those fifty lives were none of my doing. They brought it upon themselves—worshiping a monster that delighted in slaughter, trading human lives for comfort. Retribution was inevitable."
"Don't make me laugh!" she spat. "You're the real monster, Obanai!"
Obanai lowered his gaze, voice heavy.
"You're right. My hands are stained with sin. I joined the Demon Slayer Corps, devoting myself to killing demons, only to ease the weight of that guilt."
He lifted his head, eyes burning with resolve.
"But even so—I still yearn for the light. I still wish to protect the beauty that exists in this world. And I will never allow you to destroy it."
Obanai's tone hardened.
"The Iguro clan ends here. This accursed bloodline should have perished long ago. Farewell, Iguro Maharu (OC)."
"Serpent Breathing, Second Form: Narrow Headed Poison Fang!"
In an instant, Obanai vanished from sight, reappearing behind the serpent demon.
With a single, decisive strike, his blade flashed—cleanly severing her neck.