The cavern breathed.
Rion Valen felt it the moment he stepped through the holy barrier and into the sealed abyss. The air was cold—not the natural chill of underground stone, but a biting cold that clawed at the soul. Even his breath came out thin and white, like the cave was trying to claim it before it reached the air.
The elders had warned him this place was forbidden.
Only the most trusted of the Order were allowed to enter.
Only one task was permitted: purification.
Rion tightened his grip on his silver exorcist blade, its runes glowing faintly in the darkness. His footsteps echoed on the rough stone floor as he descended deeper, one quiet, careful step at a time.
He was alone.
By choice.
He replayed the conversation from this morning.
"Why you?" Elara had asked, gripping his sleeve with trembling fingers.
Her pale-gold eyes shimmered with worry. "You're the youngest Saint-tier exorcist in the Order. They shouldn't send you alone."
Rion had forced a smile.
"It's just a fragment. Not the real Demon King. I'll be back before sunset."
She didn't smile back.
"Promise?"
He couldn't promise. Not truthfully. So he'd stayed silent.
Now, as the stone walls widened into a cathedral-sized cavern, he wished he had answered her.
A sound rose from the darkness—not quite a heartbeat, not quite a pulse, but something alive. A slow, rhythmic vibration that made the ground tremble faintly beneath his boots.
Rion raised his blade.
The cavern's center was illuminated by a floating mass of black crystal, suspended by no visible force. It pulsed with dim, sickly red veins of light. The crystal wasn't large—barely the size of a human heart—but the oppressive aura it emitted was overwhelming, pressing on his lungs and skull.
This was it.
The last remnant of Azrath the Ruinborn, Demon King of the second age.
Destroyed centuries ago.
Only a tiny fragment remained.
This very fragment.
Rion whispered a prayer, and holy light gathered around his left hand.
"By the vow of purity," he murmured, voice steady, "I sever the ties of darkness. Return to ash. Be unmade."
His hand glowed brighter, light forming a sphere. The runes on his blade burned with white heat.
He approached the crystal.
The heartbeat-like sound intensified.
Thump… thump… THUMP…
Rion steadied his breath.
This was standard procedure: touch the fragment, release holy energy, let the artifact crumble. He had trained for this. Everyone said it was easy.
But standing here, the cavern trembling, the aura suffocating, he felt… watched.
He extended his glowing hand.
His palm hovered inches above the crystal.
The crystal pulsed.
Rion froze.
It… reacted?
Fragments weren't supposed to move.
"Don't tell me…" he whispered.
Before he could pull away, the crystal surged toward him as if alive.
His hand made contact.
And the world exploded.
A shockwave of shadow burst outwards, slamming Rion's body against the stone floor. The impact stole his breath. His vision blurred. Something hot—scalding—spread across his chest as the crystal melted like molten ink, spreading across his skin, sinking beneath it.
Rion screamed.
The shadows burrowed deeper. Tendrils crawled up his neck, into his spine, forcing themselves into his body like a parasite seeking a host.
His own holy light flickered, fighting.
For a moment, it pushed the darkness back—but then the darkness surged again, swallowing the light whole.
An ancient voice echoed inside him.
Low. Resonant. Whispering directly into his soul.
"So… this time, it's you."
Rion choked, clutching at his chest. His heart hammered violently.
"Get out…!" he gasped. "You're a fragment. You're not supposed to—"
"Not supposed to think?"
The voice chuckled.
"Not supposed to feel?*"
A cold hand—made of pure shadow—seemed to press against the inside of his ribcage.
"Not supposed to choose a vessel?"
Rion slammed his back against the wall, trying to breathe, trying not to panic. "I am an exorcist. I purify demons. I do NOT—"
"Purify?"
The voice laughed louder, bitter and mocking.
"Oh child, you touched the heart of a king. You do not purify me. You become mine."
Sudden agony ripped through him.
A burning sigil carved itself across his back—like hot iron branding his skin. He howled as it pulsed, locking into place. His vision whitened. His ears rang. The voice grew louder, drowning out all else.
"You will carry me, willingly or not."
Rion felt consciousness slipping.
The last thing he heard before darkness claimed him was the ancient whisper:
"Sleep, little exorcist. When you wake… we begin."
He didn't know how long he was unconscious.
But he jolted awake to shouting.
Bright light blinded him. His head throbbed. His limbs felt heavy.
He blinked through the haze.
Holy knights stood at the cavern entrance—twenty, maybe more. Their blades were drawn. Their armor radiated holy fire. Their expressions were horrified.
"What… what happened?" Rion groaned, pushing himself up.
Then he saw their eyes.
Fear. Disgust. Betrayal.
One knight pointed at him, voice cracking.
"Th-the sigil on his back! That's the Mark of Binding!"
Another shouted:
"He's corrupted!"
A third:
"He's been possessed!"
Rion staggered upright. "Wait—no—listen—I can explain—"
But he couldn't.
Because the voice in his head spoke again, soft and pleased.
"They smell it. The bond. They know you're mine."
Rion's blood turned to ice.
"Shut up," he hissed under his breath. "Don't speak—"
The knights heard him and recoiled. One lifted his blade.
"Exorcist Rion Valen," the lead knight declared, "by decree of the Holy Vows Order, you are hereby condemned as a corrupted vessel. Surrender… or be purged."
Rion froze.
Surrender?
They would kill him.
No questions.
No trial.
Just execution.
His heart pounded. His breath trembled.
This wasn't supposed to happen.
He had done nothing wrong.
He had followed orders.
But the brand on his back burned like a fresh wound.
The demon inside him whispered lazily:
"Run."
Rion ran.
The knights lunged after him, holy blades slicing through the air. Rion dodged clumsily, still dizzy, still weak, scrambling through the collapsing cavern. Light blasts struck the walls near him, sending shards of rock flying.
He barely made it through the barrier before someone grabbed his arm. Rion swung his blade on instinct, deflecting the strike.
He didn't look back.
Didn't breathe.
Didn't think.
He just ran.
He didn't stop running until the forest swallowed him whole and the cavern vanished from sight.
And he knew—
his life would never be the same again.