The worthless Ex-Convict returns to rule the world.

CHAPTER 5: The Lethal Gas Purge

NEARLY TWO HOURS LATER…

"Purge," Old Marsh whispered, his face pressed flat against the amber energy barrier. "They're running a purge."

The warning didn't come with the usual frantic blare of the containment sirens. In three years, Eren had learned every sound the Iron Abyss made—the harsh buzz for cell rotations, the dull chime for guard shifts, the screaming horn for riots.

This was a single, soft, mechanical chime. Soft as a whisper, ringing through the wet stone corridors of Sub-Level Zero.

"Not a purge," a hoarse female voice called from three cells down. "Purges get announced over the comms. They're just cycling the vents."

"I've been in this hole eleven years!" Marsh snapped back, his fused, poison-warped fingers trembling against the barrier. "I know what it sounds like when they're getting ready to clean house!"

The chime sounded a second time.

Then came the voice—calm, synthesized, utterly devoid of emotion, filtering down from the ceiling grates:

"Attention inmates. Atmospheric purification cycle commencing in sixty seconds. All personnel clear Sub-Level Zero. This is a mandatory procedure."

A sudden wave of noise rippled through the cellblock—chains scraping on damp stone, boots sliding, men who had given up on living years ago suddenly clawing at their cell doors in a blind panic.

"Forty-five seconds."

Eren pushed himself up into a sit, his back scraping against the curved obsidian wall.

The green-tinted black-site mana gas was already creeping out of the high intake vents. Earlier, Hobbs had brought a poisoned ration tray to break his stomach, but that had just been a trial run. This was the actual order Warden Gideon Vane had logged. The Tyrell Clan didn't want to leave anything to chance.

"Thirty seconds."

Eren looked down at his arms. The heavy obsidian fetters around his wrists were webbed with deep, glowing fractures. Where the Tyrells had ripped out his Spirit Marrow three years ago, a new core sat in his chest—a golden, hungry thing forged directly from the toxicity he'd digested over the last hour.

"Fifteen seconds."

The air in the cell grew heavy, tasting of copper and bitter lye. Across the aisle, Marsh fell to his knees, his throat making a wet, rattling sound as the pre-charge gas hit his decayed lungs.

"Five, four, three, two, one..."

Eren closed his eyes.

"Purge commencing."

The vents shrieked as the primary high-pressure seals blew open.

It poured from the ventilation shafts in thick, churning columns, so dense it turned the air into something closer to liquid than vapor. The cell disappeared. The walls disappeared. Even the light from the flickering ceiling fixture vanished, swallowed by a gray-black tide that filled every corner of Sub-Level Zero with lethal, concentrated mana poison.

Eren took the full blast directly in the face.

The gas was inside him now, filling his chest, his throat, his stomach, dissolving tissue and corrupting blood. This was not the slow poison of the Mist. This was a purge. A concentration so high that it stripped the flesh from bones in minutes.

Across the hall, the muffled sounds of choke-screams cut off one by one as the other inmates collapsed.

Eren fell forward, his knees slamming into the wet flagstones. His vision whited out. His organs were literally dissolving; his blood turned thick as slush as the concentrated black-site gas tried to tear his pathways to shreds.

“This is it,” he thought, his chest heaving uselessly for air that wasn't there. “This is how I die?”

His organs were failing. He could feel them shutting down, liver, kidneys, lungs. His blood was turning to sludge. His brain was starving for oxygen. The purge was doing exactly what it had been designed to do. It was killing him.

The gold light in his chest dimmed down to a faint, dying ember.

“No,” he thought. “Not yet. Not like this.”

He tried to breathe. The gas filled his mouth, his throat, his lungs—more poison than air. His body convulsed. His vision went dark.

The light flickered again. And then—It moved.

Then, deep in the marrow of his ribs, something snapped into place.

The ancient Sovereign Healer Bloodline didn't just fight the purge—it devoured it.

The instant the lethality reached a critical mass, the golden core in his chest flared into a blinding sun. The dark green poison flooding his lungs was forcibly dragged through his newly formed pathways, stripped of its rot, and converted into pure, boiling kinetic energy.

BANG.

The obsidian fetters around his wrists shattered completely, exploding into black dust.

Eren didn't choke. He didn't scream.

He slowly stood up in the pitch-black, toxic cloud, opened his mouth, and pulled the entire room's worth of lethal purge gas deep into his lungs.

The golden glow beneath his skin burned bright enough to illuminate the stone walls. His withered muscles filled out, his broken pathways knitted together, and three years of rot vanished in a single, roaring breath.

He looked toward the cell doorway where the energy barrier had shorted out.

"Thanks for the meal, Warden Vane," Eren whispered into the dark, his voice carrying a calm, terrifying weight.

His eyes flashed pure, undivided gold in the pitch-black cell. The deadened pathways in his body were overflowing with power, the golden core in his chest roaring like an engine fueled by the very purge sent to destroy him.

He slowly looked down at his hands, watching the golden aura dance across his skin, burning away three years of prison filth, rot, and scar tissue.

"Now it’s my turn to return the favor."

Every breath of poison only made him stronger. Every second in this deep-sea grave had cleared away the naive fool who had trusted Lyra Tyrell. They had ripped out his Spirit Marrow and buried him miles beneath the ocean to ensure he would never seek retribution.

They thought they had killed him. Instead, they had given him the ultimate weapon.

A cold, lethal smile spread across Eren’s face as he turned his gaze toward the dark corridor outside his cell.

"Just you wait, Lyra Tyrell," he murmured, his sovereign pressure causing the stone floor to crack beneath his boots. "Enjoy my spirit marrow while you can. Because when I walk out of this abyss, I'm taking back everything you stole and tear the entire Tyrell clan to the ground."