Darkness wasn't supposed to have shape.
It wasn't supposed to breathe.
It wasn't supposed to pulse like a sleeping heart.
Yet as Hayate stepped off the final floating stair and entered the black void beneath the inverted city, the darkness shifted—quietly, like silk sliding across steel.
Flare clung to his sleeve again, vibrating with terror.
"O-okay… okay… maybe it's not too late to go back?" We could pretend we didn't hear the giant knight and EXIT THIS NIGHTMARE! Yes! Great plan!
Hayate didn't answer.
He couldn't.
The moment he crossed into Floor 6, the world… changed.
The abyss inverted.
The blackness that had surrounded them twisted violently upward—as if gravity reversed—spinning into a swirling vortex of shadows. Runes—ancient, glowing, the color of dying stars—rushed across the walls of the void, forming a spiraling tunnel around him.
thum…
The heartbeat grew louder.
thum…
And louder.
THUM—
Until Hayate's own pulse synced with it.
Flare whimpered.
"Hayate…? Why does this place sound like it's ALIVE? And why is it beating like a boss monster having a midlife crisis?"
Hayate's eyes darkened.
"That's not the dungeon's heartbeat."
"…Then whose!?"
He closed his eyes.
"…Mine."
The abyss roared.
A deep tremor surged through the entire floor—as if the world recognized the truth he had spoken. The swirling shadows parted, revealing the full expanse of Floor 6.
Flare choked.
"Oh… oh no. Nope. HAYATE. WHY DOES THIS LOOK LIKE THE INSIDE OF A COSMIC BEAST'S RIB CAGE!? WHO DESIGNED THIS!?"
She wasn't exaggerating.
Floor 6 was… wrong.
A massive cavern—too vast to be natural, too alive to be stone—stretched out before them. The ceiling was a dome of pulsating, vein-like constellations. The ground was smooth obsidian, cracked by rivers of glowing crimson energy. Towering "ribs" of black crystal curved overhead, each one inscribed with divine seals—broken, shattered, or half-erased.
The air tasted metallic.
Thick.
Electric.
And from the center of the immense cavern rose a colossal structure:
A heart-shaped crystal, cracked and partially buried, chained by celestial bindings that glowed with fading light.
Each pulse emanating from it shook the air:
THUM—
THUM—
THUM—
Flare whispered:
"…Hayate… is that…"
"My core."
The word left his mouth without hesitation.
He didn't understand how he knew.
He didn't need to.
His soul recognized it instantly.
The Heart of Oblivion—his Devouring Star Core—was sealed here.
Flare waved her hands frantically.
"W-wait, wait, WAIT. Your core is THAT!? That building-sized, universe-breaking, god-annoying, planet-eating cosmic tumor—THAT is part of YOU!? How do you even fit that inside a human body!?"
Hayate didn't look at her.
He was already stepping forward.
The moment his foot touched the obsidian floor—
The dungeon responded.
WRAAAAAAAAGH—!!!
Dozens of chasms across the cavern tore open, belching out torrents of black mist. Shapes began crawling from the depths—shadows with form but no face, limbs with claws but no body, silhouettes that flickered like ghosts.
Flare's jaw trembled.
"O-oh no… shadow monsters… w-why does every floor get WORSE!?"
Hayate's presence alone made the nearest shadows freeze.
Then—instantly—they shattered into dust.
The others recoiled violently.
Like prey recognizing a predator.
Or servants recognizing their sovereign.
The ground shook.
A voice emerged from beneath the core—heavy, ancient, echoing like a star collapsing.
"…He… has returned…"
"…The Sovereign… awakens…"
"…Prepare… the Heart…"
Flare flailed her arms.
"NO! DO NOT PREPARE ANY HEART! KEEP ALL HEARTS UNPREPARED—!!"
But the darkness had already responded.
A massive circle of runes ignited beneath Hayate's feet—layer after layer of star-inscribed sigils, spinning and locking into place. The runes resonated with his heartbeat, rising in pitch and brightness.
The cavern brightened.
But it wasn't light.
It was recognition.
"Sovereign," the voices echoed, "the seal weakens. Your core calls to you."
Hayate stepped forward.
One step.
The entire cavern rumbled.
Two steps.
The heartbeat doubled in intensity.
Three steps—
A hand grabbed his collar and yanked him backward.
"NO YOU DON'T!" Flare shouted, kicking the air like a drowning squirrel. "You are NOT walking into a giant cosmic core like it's your bedroom! What if it explodes!? What if it absorbs you!? WHAT IF IT WAKES UP AND EATS YOU!?"
"It is me," Hayate said calmly.
"That does NOT make it better!"
Then—
BOOM—!!!
A massive shockwave tore through the cavern, sending both of them flying backward.
Hayate slid across the stone and landed silently.
Flare slammed face-first into his back.
"My EVERYTHING hurts…"
Hayate stood.
Slowly.
Eyes narrowing.
Because the core was… opening.
Not physically.
Spiritually.
A vertical fracture spread through the giant heart-shaped crystal, pouring out endless black light. The ground beneath it split, forming a massive altar of orbiting stone shards. Runes spun around it like satellites.
And from within the crack…
A figure stepped out.
A woman.
Or at least—
Something wearing the shape of one.
She was tall, ethereal, draped in robes made of starlight that changed shape with every blink. Her hair flowed like black cosmic gas. Her eyes were galaxies—literal galaxies—swirling with nebula colors.
Her voice hummed like overlapping chords:
"Reincarnated fragment of the Devouring Star… You stand before your Heart. Your core. Your truth."
Flare squeaked.
"AHHH—A CELESTIAL GHOST LADY! AHHH—SHE'S SO PRETTY I WANT TO RUN AWAY—!!"
Hayate stared, silent.
The woman tilted her head, smiling warmly—too warmly.
"Do you not recognize me, Sovereign?"
"…No."
Her smile widened.
"Then allow me to reintroduce myself."
The shadows trembled.
The core pulsed.
Her form stabilized, light bending around her as her voice echoed through the cavern:
"I am Lumeria, the Star-Scripted Warden."
She raised a hand, and the chains around the core glowed in response.
"The gods created me… to guard you."
Flare blinked.
"Guard… him? Guard HIM!? Him!? The superweapon!? Why would anyone guard HIM!?"
Lumeria's expression softened.
"Because the world feared him… but they feared what would replace him even more."
Hayate's voice was sharp.
"What do you mean by 'replace'?"
Lumeria hesitated.
"Another Devouring Star."
The cavern went silent.
Even Flare was speechless.
Lumeria stepped forward, her feet not touching the ground.
"The gods sealed your core not simply to imprison your power… but to prevent the birth of a second Sovereign. Without you, the balance of the worlds would collapse."
Hayate frowned.
"I am reincarnated. So the seal failed."
"No."
Her gaze grew heavy.
"You were allowed to reincarnate. But your core remained sealed—until the moment your soul was strong enough to reclaim it."
Flare gasped.
"So the dungeon—THIS WHOLE NIGHTMARE—was a test!?"
Lumeria nodded.
"A trial. To see if you would reclaim your path… or abandon it."
She gazed deeply at Hayate.
"You have chosen."
The ground cracked beneath Hayate's feet as his aura flared—black, star-scorched energy swirling around him.
The shadows in the cavern bowed.
The ribs of crystal trembled.
The core pulsed violently.
thum—
thum—
THUM—!!
Hayate stepped forward again.
Lumeria raised a hand to stop him.
He didn't.
She held her ground, but her eyes widened at the sheer force behind his aura.
"Wait."
Her voice shook.
"You are not ready."
Hayate's eyes sharpened.
"You said the seal weakens. I will break it now."
"No! If you touch it in your current state, it will consume your body and mind entirely. You must first—"
Then—
Everything exploded.
BOOOOOOOOM—!!!
A massive blast shot out from the core, blowing Lumeria backward and shattering dozens of floating platforms. Flare screamed, clinging to Hayate's hair like a lifeline.
Lumeria stabilized midair, eyes glowing with alarm.
"No… it's too soon…"
Cracks surged across the core—thousands of them—spreading like fractures in glass.
"It's waking up," Hayate muttered.
Lumeria's voice trembled.
"No… something ELSE is waking up!"
"What?"
Before she could answer—
A new voice echoed across the cavern.
A deep, ancient, monstrous voice.
One not meant for mortal hearing.
—"Sovereign…"—
—"…Your predators… have arrived…"—
The entire floor began collapsing.
Ribs of crystal shattered.
Rivers of crimson energy burst open.
The ground trembled like the heartbeat of a dying god.
Lumeria's face paled.
"No… NO—! It found you! The thing sealed BEHIND your core—he has sensed your arrival!"
Flare grabbed Hayate's ear.
"WHAT THING!? WHY WAS THERE SOMETHING BEHIND THE CORE!? WHY IS THAT A SENTENCE THAT EXISTS!?"
Hayate's eyes narrowed.
"Name it."
Lumeria whispered:
"…The Hollow Star. The antithesis of your existence."
Hayate stepped forward.
"What does that mean?"
Flare shrieked:
"IT MEANS AN EVIL VERSION OF YOU IS ABOUT TO BREAK OUT, YOU CRAZY PERSON—!!"
The core cracked open fully.
A torrent of black, hollow energy erupted upward, shaping itself into a monstrous silhouette with countless eyes and a gaping, starless mouth.
Lumeria screamed:
"RUN—!!!"
Hayate didn't.
He walked toward it.
The floor exploded beneath him.
The air shattered like glass.
The Hollow Star roared.
And for the first time since entering the dungeon—
Hayate felt something familiar.
Not fear.
No hesitation.
But war.
His past.
His enemy.
His reflection.
The Heart of Oblivion was awakening.
And the monster sealed behind it was awakening, too.
Hayate's voice echoed through the collapsing cavern:
"Then I will destroy it."
The Hollow Star screamed.
The dungeon trembled.
Lumeria's eyes widened in disbelief.
And Flare fainted for the 50th time.
Floor 6 had begun.
And Oblivion… was coming home.