Arthur opened his eyes.
The ceiling above him was cracked, stained with water damage. The dim, flickering light of a broken streetlamp bled through the single window of his small, rundown apartment in Sector 4.
He didn't remember walking home.
He sat up slowly, his skull throbbing with a dull, persistent ache. He looked down at his hands.
Dried, blackened blood flaked off his knuckles. The metallic scent of ozone and rot clung to his clothes.
I killed the Ghoul, Arthur thought, forcing his fragmented memories into order. I took the core. And then...
Nothing.
A blank, terrifying gap in his memory between leaving the graveyard and waking up on his rusted bed.
Arthur looked at his shadow cast against the peeling wallpaper. For a fraction of a second, the shadow didn't match his posture. It looked broader. Taller. Almost... horned.
He blinked, and the shadow snapped back to normal.
[Notice: Empathy Suppression Active. Corruption Level: 2%.]
Arthur stared at the notification. The System wasn't just suppressing his emotions; it was actively trying to pilot his body when his consciousness weakened.
A cold, isolating realization settled in his chest.
He wasn't just fighting monsters anymore. He was fighting for the driver's seat of his own existence.
Arthur stood up, splashing cold water from a rusted sink onto his pale face.
"I need to get stronger," Arthur whispered to the empty room. "Before it does."
He grabbed his tattered black cloak, hiding his academy uniform and his bruised face. He checked his pocket. The faintly glowing green orb of the Level 8 Elite Boss was still there.
He didn't head toward the Academy.
He headed deep underground.
...
Neon lights flickered violently above the Underground Sector, casting broken shadows across wet brick walls.
The air reeked of cheap alcohol, rust, and illegal potions. This was the Black Market—a lawless zone where Hunters, mercenaries, and criminals traded without taxes... or questions.
Arthur moved through the crowded alley, ignoring the flashy stalls. Glowing swords. Colorful elixirs. Worthless distractions.
He already knew what he wanted.
At the end of a dead-end street, he pushed open a heavy, iron-reinforced door.
A bell chimed harshly.
The shop was cramped, dusty, and packed to the ceiling with strange artifacts and monster remains.
Behind the counter sat an old man with a scarred face and a whirring, mechanical right eye. A thick cigar burned between his lips.
"We don't buy slime cores or rat tails, kid," the old man grunted without looking up, cleaning a rusted dagger. "Try the recycling center if you're broke."
Arthur didn't respond.
He stepped forward... and placed the faintly glowing green orb on the scratched wooden counter.
Thud.
The mechanical eye whirred.
The old man stopped cleaning the dagger. The cigar shifted in his mouth.
"...A Corrupted Ghoul Core," he muttered, his tone shifting from dismissive to dangerously alert.
He leaned closer, inspecting the dense, swirling dark energy inside the orb without touching it.
"Fully intact. Level 8 Elite Boss."
His mechanical eye snapped up, lingering on Arthur's bruised face and bloodstained cloak. It was a sharp, calculating look. The look of a scavenger evaluating a predator.
"You didn't find this," the old man stated quietly. "You survived it."
"Are you buying or not?" Arthur asked, his voice completely flat.
A heavy silence fell over the shop.
In the Black Market, asking too many questions was a good way to invite a knife to the throat.
The old man slowly exhaled a cloud of gray smoke.
"Official Guild price is 5,000 credits," he said, tapping the ash from his cigar. "But you can't sell it there without a high-tier license. Here? No questions, no records. I take a cut. 4,000."
"4,500," Arthur countered instantly, his pitch-black eyes locking onto the old man. "Or I take it to the Rat King's stall down the street."
The old man chuckled, a dry, raspy sound. He opened a heavy safe under the counter.
"4,500 it is. You've got guts, kid."
He tossed a sleek black credit card onto the counter.
Arthur held it for a second. Just an hour ago, he couldn't afford a proper meal. Now, he could survive for months.
But survival wasn't his goal. Domination was.
"Show me your Necromancer skill books," Arthur commanded.
The old man barked another laugh.
"Necromancer? That trash class?"
He reached under the counter and pulled out a worn, dark-purple book, throwing it onto the table. It hit the wood with a heavy, unnatural thud.
"This cursed thing has been rotting here for three years."
Arthur placed his hand on the leather cover. It felt unnaturally cold.
[Item: Skill Book - Summon Poison Skeleton]
[Tier: Common (Corrupted)]
[Effect: Summons a Level 1 Poison Skeleton]
[Warning: 90% chance of fatal backlash upon learning.]
"A suicide manual," the old man snorted. "Anyone who tried to learn it either died screaming... or wished they had."
A corrupted skill. Fatal to anyone who used it.
Garbage for the rest of the world.
But Arthur wasn't bound by the rules of the world.
"I'll take it," Arthur said. "Deduct 500."
The old man stared at him as if looking at a walking corpse, but processed the payment anyway.
"Your funeral, kid."
Arthur ignored him.
He grabbed the book and stepped back out into the neon-lit alley.
He didn't go home.
He slipped into an abandoned, lightless side street, checking his surroundings carefully.
No footsteps. No presence.
Only the sound of the rain.
He raised his hand.
In his mind, his original skill appeared:
[Summon Skeleton Lv.1]
In his other hand—the corrupted book.
Arthur's eyes darkened, the oppressive aura of the anomaly inside him leaking out.
"System..." Arthur whispered. "Use Absolute Synthesis."
[Ding!]
[Target 1: Summon Skeleton (Lv.1)]
[Target 2: Summon Poison Skeleton (Corrupted)]
[Commencing Skill Synthesis...]
A violent surge of purple energy erupted from his hands, illuminating the alleyway like a strobe light.
But the corrupted book didn't just resist. It fought back.
Thick, toxic green smoke poured out of the pages, wrapping around Arthur's wrists like biting snakes.
"Burn..." a raspy, disembodied voice hissed directly into his mind.
Arthur gasped, his knees buckling as the venomous mana violently invaded his nervous system. His vision blurred, swimming with agonizing, hallucinogenic colors. He felt a sickening heat spreading through his veins, as if he had just injected boiling acid.
He didn't scream. He bit the inside of his cheek so hard he tasted blood.
He forced his monstrous willpower into the storm, crushing the rebellious corruption with the sheer, unadulterated weight of his hatred for weakness.
"Submit!" Arthur roared through bloody teeth.
CRACK.
The book violently shattered.
It disintegrated into particles of dark, jagged light, flooding directly into Arthur's chest.
He collapsed against the wet brick wall, panting heavily, his body trembling from the violent physical toll of the forced integration.
The system's voice rang out, but it sounded warped, almost static.
[Synthesis Successful.]
[Corruption Partially Integrated.]
[Unknown Side Effect Detected in Host's Mana Circuits.]
[Skill Mutation Complete.]
Arthur's breath slowly steadied. He wiped the blood from his mouth.
He opened his status panel to view the new skill.
His pitch-black pupils shrank to pinpricks.
"...What the hell is this?" Arthur whispered, his voice trembling slightly.
It wasn't just a list of stats.
The text on the blue screen was pulsing faintly, as if breathing.
A skill like this... shouldn't exist at Level 3.
"...This isn't a skill," Arthur murmured into the dark alley.
"It's alive."