Demon Lord reborn as The Hero's Child

Absolute silence.

The strange sensation disappeared, leaving no trace.

Kōya stood there on the ancient road for several seconds, waiting.

Nothing. No answer. No movement in the shadows. Only the cold wind passing softly through the dead trees.

He shook his head aggressively, trying to clear his compromised thoughts. ”Why the hell did I think of her?”

He looked toward the looming structure at the end of the ancient road. Then, he continued climbing.

He had no idea that something incredibly dangerous was already waiting for him ahead.

The dense trees finally ended abruptly.

Kōya stepped out of the forest and onto a massive plateau.

And stopped entirely.

The structure towering before him was beyond enormous. For several long seconds, his brilliant mind could do nothing but stare.

A colossal, sprawling stone complex rose directly from the valley floor. Its impenetrable outer white walls climbed significantly higher than the tallest surrounding trees. Ancient, fortified towers pierced the gray sky like spears. Massive stone stairways led toward enormous, iron-banded gates.

The underlying architecture was unmistakably, purely Heroic. It was majestic and holy.

But it had been violently changed.

Massive, jagged black metal structures had been bolted and welded onto the pristine old walls. Thick, humming lightning conductors ran in chaotic webs from tower to tower. Dark, pulsing magical cables crossed the ancient white stone like parasitic veins. Enormous, humming crystal devices had been crudely embedded directly into the masonry.

Blue-white lightning flowed continuously through the dark crystals.

Tattered, blood-red Demon banners draped mockingly from the holy towers. Some of the ancient Hero statues flanking the gates had been entirely replaced with grotesque, monstrous gargoyle figures.

The original, holy structure had not been destroyed.

It had been occupied. Brutally modified. Thoroughly corrupted.

Kōya stared up at the enormous, yawning entrance.

”So, this is the Hero’s Lair.”

The words felt strange on his tongue. He had heard the wounded scout utter the name only an hour earlier. Now he understood the distinction.

The Hero’s Fortress was the protected, sealed sanctuary hiding beyond the Bridge of Hope. That place had been safely hidden behind an impenetrable wall of ancient protection.

This was fundamentally different.

The Hero’s Lair was an ancient, offensive Hero structure that had completely fallen into demonic hands. And whoever currently controlled it had deliberately turned the beautiful old Heroic architecture into a terrifying, mechanized Demon stronghold.

Kōya scanned the ground near the gate.

There were fresh, chaotic marks around the massive entrance. Heavy, muddy boot prints. Splattered blood. Broken iron chains discarded on the stone.

Someone had been forcibly brought through these gates very recently.

He stepped forward, his boots echoing.

The massive iron gates stood wide open.

Tactically, that was far worse than finding them securely closed and locked. It was an invitation.

Kōya entered the stronghold.

The temperature instantly plummeted. The hollow sound of his slow footsteps echoed loudly through the enormous, vaulted passage.

His left hand remained hovering inches from the Hero Sword.

The interior was even more disturbing. Ancient, beautiful Hero statues lined the massive stone walls. Some were missing their marble heads entirely. Others had been violently covered with fresh, dark blood and demonic symbols.

One massive, ancient mural painted across the ceiling showed legendary Heroes fighting demons beneath a brilliant golden sky.

Someone had recently, meticulously carved a jagged Demon crest directly across the painted faces of the Heroes.

Kōya stopped before it, looking up. His expression hardened into stone.

”People really don’t change.”

He continued down the corridor.

The passage eventually opened into a massive, cavernous central hall.

There were chaotic remnants of recent demonic activity scattered everywhere. Heavy wooden tables overturned. Discarded weapons. Empty, blood-stained iron cages. Broken chains. Massive, humming mana containers hooked to the walls.

Several large, dark crystals standing in the center of the hall had been drained almost completely of their energy.

Kōya approached and examined one of the dead crystals closely.

The residue inside the glass was undeniably demonic.

But there was something else subtly mixed into the arcane signature.

Human mana.

His lip curled in disgust. ”What exactly are they doing in here?”

He moved deeper into the shadows of the hall.

Then, his eyes caught something.

A small strip of pale blue cloth was caught securely on a jagged, broken piece of metal protruding from one of the cages.

Kōya froze.

He knew that exact cloth.

He reached toward it slowly. His scarred fingers trembled despite his iron control.

”Mom.”

He pulled it free from the metal.

The cloth was violently torn. There were dark spots of dried blood staining the edge. But the residual, panicked mana remaining locked within the fabric was absolutely unmistakable.

Mizuki had been right here.

Kōya closed his fist tightly around the cloth, burying it in his palm.

”Where did they take you?”

A sound echoed loudly through the cavernous hall.

Clang.

Kōya snapped his head up.

Another deliberate sound.

Clang.

Heavy boots against stone. Someone was approaching from the shadows.

He slowly, carefully placed the torn blue cloth inside his coat.

His right eye instantly darkened, the violet-black void expanding. Viscous, terrifying Demonic Aura began violently gathering around his right side.

In immediate response, the heavy Hero Sword across his back hummed, resonating with the Heroic Aura in his left side. Brilliant golden light appeared along its razor edge.

Kōya waited, perfectly balanced.

The sound of the footsteps stopped.

Absolute silence.

Then, without warning, blinding blue-white lightning exploded across the far end of the hall.

BOOM!

A massive, concentrated bolt of electricity arced directly toward him.

Kōya didn’t draw his sword. He simply raised his right arm.

A thick, impenetrable wall of swirling black Demonic Mana instantly formed in the air in front of him.

The massive lightning strike slammed aggressively into the dark barrier. The kinetic impact was staggering; it shattered several ancient stone pillars flanking Kōya, sending debris raining down.

Kōya slid backward across the smooth floor, his boots carving deep, smoking lines into the ancient stone to arrest his momentum.

He lowered his right arm and looked through the smoking, dissipating barrier.

A tall figure stood relaxed at the opposite end of the hall.

He was imposing, radiating complete calm. A heavy, dark sword rested casually in his right hand. Violent, crackling blue-white lightning crawled constantly across the dark steel blade.

The man’s cold eyes settled squarely on Kōya.

For a long moment, neither warrior moved.

Then, the stranger’s gaze drifted from Kōya’s face to the glowing golden hilt resting over the boy’s shoulder.

His arrogant expression shifted into pure recognition.

”That sword.”

Kōya said absolutely nothing. He remained in his stance.

The stranger took one slow, deliberate step forward, his boots echoing. ”Where did you get it?”

Kōya’s grip tightened around his demonic aura. ”Answer my question first.”

The stranger smiled faintly, amused by the defiance. ”You came all the way into this stronghold alone, and you actually still think you are the one asking the questions here?”

Kōya reached over his shoulder with his left hand and slowly drew the Hero Sword.

Blinding, radiant golden light flooded the gloomy hall, casting long, sharp shadows as it drew from the Heroic reserves already inside him.

The stranger studied the blade. ”Interesting.”

Kōya leveled the golden blade, pointing the tip directly at the man’s chest. ”I am looking for my mother.”

The man’s amused smile vanished instantly. ”Your mother?”

”Mizuki Amane.”

The name echoed loudly through the cavernous, empty chamber.

The stranger remained completely silent.

Kōya’s violet-black Demonic Mana aggressively rose, swirling violently around his legs. ”Where is she?”

The man looked at the furious boy for several long seconds. Then, his gaze returned to the glowing Hero Sword.

”So. You really are Seiya’s son.”

Kōya’s expression did not change. ”You knew my father.”

The man slowly lifted his crackling Lightning Sword, resting the flat of the blade against his shoulder. ”I knew of him. I stood against him.”

”Where is my mother?”

The stranger deliberately ignored the question. Instead, he clinically studied Kōya.

He analyzed the pure holy light of the Hero Sword. Then, he looked at the suffocating, violent black Demonic Mana aggressively surrounding the boy’s right side. Then, the golden Heroic Aura peacefully gathering around his left.

The stranger’s eyes narrowed.

”Seiya never once mentioned to me that he had a son.”

Kōya’s voice dropped into a terrifying, sub-zero register. ”He didn’t have the chance.”

A violent flash of blue lightning crossed the stranger’s dark eyes. ”Then the great Hero is finally dead.”

Kōya said absolutely nothing. The heavy, murderous silence was answer enough.

The stranger slowly lowered his sword, pointing it at the floor. Crackling lightning began aggressively spreading across the stone tiles like a web. The ancient Heroic symbols carved beneath Kōya’s boots violently flickered and sparked as the electricity passed over them.

Kōya watched the arcane display carefully, his analytical mind processing the threat level.

The man’s mana was immense. It was refined. Highly condensed. Controlled to a lethal degree.

Kōya had fought towering Demon Generals. He had slaughtered elite assassins. He had butchered monsters that could easily crush an entire squad of ordinary adventurers.

This was fundamentally different.

The ambient pressure alone was enough to make the air in the massive hall feel thick and unbreathable.

The man finally spoke, his voice echoing with absolute authority.

”My name is Zeref.”

Blinding, concentrated lightning gathered around his dark blade.

”I am the Lightning Sword Demon Peer.”

Kōya’s grip tightened.

Demon Peer.

So, this was finally one of them. The apex predators. One of the god-like beings that stood high above the ordinary demonic hordes. One of the overwhelming powers that had broken his father.

One of the primary forces behind the tactical operation that had dragged his mother away in chains.

Kōya smoothly shifted his footing into a flawless combat stance. ”My father fought you.”

Zeref tilted his head slightly, almost mockingly. ”Not directly. I merely secured the prize.”

”Then tell me where Mizuki is.”

Zeref’s eyes gleamed with cruel satisfaction. ”You have your legendary father’s sword.”

Kōya didn’t move an inch.

”You somehow possess his ridiculous holy mana.”

Still nothing.

”And yet...” Zeref smiled, a chilling expression. ”...you carry something he never possessed.”

Kōya’s violet-black Demonic Mana flared aggressively in response to the taunt. ”What?”

Zeref’s gaze settled heavily on the suffocating darkness swirling around Kōya’s right side.

”The unmistakable scent of a Demon Lord.”

The massive hall became utterly silent.

Kōya’s expression remained an impenetrable mask of cold stone. ”I am not remotely interested in what you think I am.”

He pointed the blazing Hero Sword directly at Zeref’s throat.

”Tell me exactly where my mother is.”

Zeref stared at the boy. Then, he laughed quietly, the sound echoing off the stone pillars.

”You came all this way, through all that blood, blindly searching for Mizuki.”

His grip tightened aggressively around the hilt of the crackling Lightning Sword.

”But you don’t even begin to understand what you have just walked into, boy.”

Kōya took one heavy, deliberate step forward.

”I will understand perfectly after I get her back.”

Zeref raised his blade high. Blinding lightning violently exploded around his entire body, shattering the remaining stonework near him.

”Then come and take your answer.”

Kōya instantly lowered his center of gravity.

Radiant, blinding golden light gathered violently along the edge of the Hero Sword in his left hand. At the same time, thick, suffocating black flames began aggressively burning around his right arm and legs.

The two opposing powers did not merge. They fought for dominant space within his body, testing his physical limits. But neither vanished.

Kōya took one explosive step forward.

Zeref disappeared with a hint of lightning travelling upwards.

A massive, blinding bolt of blue lightning crossed the entire length of the hall in a fraction of a millisecond.

Kōya didn’t blink. He swung the massive Hero Sword in a flawless, intercepting arc.

CLANG!

The two legendary blades collided with apocalyptic force.

The resulting shockwave shattered every remaining stained-glass window in the massive hall. The ancient, indestructible stone floor violently cracked and cratered directly beneath their boots.

Kōya’s eyes widened slightly under the strain. Zeref’s physical strength was monstrous.

Zeref smiled through the blinding sparks, his face inches from Kōya’s.

”Now...”

Lethal, high-voltage lightning violently erupted from the Lightning Sword, arcing directly toward Kōya’s face.

”...show me exactly what Seiya left behind.”

Kōya roared and pushed forward with everything he had.

The ancient Hero Sword blazed with the pure, blinding gold of his awakened reserves. His suffocating Demonic Mana roared with apocalyptic black fire.

And the ancient, corrupted Hero’s Lair violently shook beneath the catastrophic clash of two devastating powers that should have never been allowed to stand together in the same world.

The true battle had finally begun.