The Oni host turned slowly, that familiar, cruel smile stretching across his young face. He clearly hadn't expected Renji to reach this deep into the dimension so quickly.
"Well, well. Look who decided to show up," he sneered.
Renji paused, completely thrown off. He had braced himself for a towering monster or an ancient beast, but standing in front of him was just a boy—a teenager, no older than sixteen.
"Uh, kid... where are your parents? And what exactly are you doing in a place like this?"
Renji asked, stepping cautiously toward him, his guard up but confused.
The boy simply smiled and shook his head, looking at Renji with pity. His eyes suddenly flooded with ink-black darkness, and a wisp of heavy, black smoke began to dance in his palm.
"So, you are the Mortal King," the boy said, his voice sounding far too old for his throat.
"I can feel the energy trying to hide around you."
Renji stumbled back a step. The sheer pressure radiating from this "kid" was suffocating, it was clearly superior to his own aura.
Who is this guy? Renji questioned himself, sweat forming on his brow.
[Identification in progress...]
[Target Identified.]
[Subject is an ordinary human male, but he is being animated by a High-Tier Entity.]
"A powerful entity? That means he's been possessed," Renji whispered, retreating further to analyze the threat. If there was an innocent life in there, this just got complicated.
[Scanning Entity...]
[Target Undefined. Data corrupted.]
"What? You can't even identify the possessor?" Renji snapped at the System.
Before the System could reply, the Oni host extended a hand toward Renji. The black smoke in his palm lashed out like a whip, coiling instantly around Renji's neck and hoisting him into the air.
"Who do you think you are?" the Oni asked, tilting his head while Renji dangled helplessly. "The 'Mortal King'?" He hissed the title like a bad joke.
Renji gritted his teeth. He forced his Necrotic aura to surge outward, blasting the smoke apart like shattering glass.
He landed softly on his feet, staring at the boy with frustration. The enemy was strong, but the vessel was innocent. How was he supposed to kill a kid?
"Wait, kid. Let's make this simple," Renji said, raising his hands in a placating gesture. "You can go home, okay? I really don't want to hurt you."
As he spoke, the boy didn't even blink. He launched several jagged blades of dark energy straight at Renji's chest. Renji was forced to dodge, weaving through the lethal barrage while trying to talk him down.
"I underestimated you," the Oni laughed, firing another blast. "You're hesitating because you're afraid of hurting a little kid."
Renji clenched his jaw. He couldn't do it. The boy reminded him too much of Hikari—young, scared, and dragged into a world of monsters.
"If I may ask," Renji said, dodging another strike and keeping his voice calm, "what do you actually want with the Lord's soul?"
The Oni smiled and finally paused his assault.
"You know what I want? I want your head. The prophecy says that once you claim the Abyss Lord's Essence, you will stop me from destroying this world. I am here to change that prophecy."
Renji's mind raced, looking for a way out, but the boy's presence was overwhelming.
"Who are you, really?" Renji demanded, stepping forward with sudden bravery. "Identify yourself."
The boy's grin widened, revealing teeth that looked too sharp.
"I am Lord Oni. The King of All Demons."
Renji took a sharp step back, genuine shock hitting him like a physical blow. Even the System reacted violently in his mind.
[WARNING: LORD OF THE DEMONS DETECTED!]
Renji took a deep breath and stood tall, pushing the fear aside.
"I am the one the prophecy speaks of," Renji declared, his voice steady. "I won't let my guard down, and I won't let you take that soul. The Essence belongs in my hands as the Mortal King. Right here, right now, I'm going to make sure you get sent back to your own world."
The Oni nodded, a flicker of appreciation in his black eyes.
"Such a brave King. Impressive. But if I kill you today, the prophecy breaks, and I will be the one to rule this world."
The boy's body suddenly erupted in crackling purple lightning.
But before the thunder could even peel, Renji moved. In the blink of an eye, utilizing his maximum speed, he was already standing directly behind the Demon King.
Renji didn't wait. He extended his hand, channeling his anger into raw power. A massive sphere of flaming green necrosis erupted from his palm, engulfing the Oni host in a violent explosion.
The smoke cleared to reveal the shattered remains of the boy's body. Renji's heart sank, the weight of guilt pressing instantly on his chest.
"Oh god... what did I just do?" he whispered, staring at the scattered pieces of an innocent child.
But then, the impossible happened. The flesh began to knit itself back together, bone snapping into place with sickening speed.
Within seconds, the Oni host stood whole again, his smile untouched.
He moved, and this time, he was faster than the wind, invisible to the naked eye. Renji's eyes darted frantically, trying to track the displacement of air.
The Oni materialized instantly, dragging his SS-Rank red sword downward in a lethal arc aimed at Renji's neck. Relying on pure reflex, Renji dipped his shoulder, narrowly dodging the decapitating strike. He countered with a heavy punch to the boy's midsection, but the Oni caught the fist effortlessly.
With a simple twist, the Oni host slammed his forehead into Renji's, dazing him, before delivering a shallow, precise cut across Renji's stomach.
Renji stumbled back, clutching the bleeding wound, his gaze locked on the glowing body of the Lord behind his enemy. "No. I am not giving up."
Both combatants drew their blades. Renji's broken weapon reformed, manifesting as a perfectly designed sword of green energy wreathed in crackling emerald lightning.
They crashed together. The impact of their swords sent a shockwave rippling through the ancient hall, fracturing the stone floor.
They exchanged blows at blinding speed.
Renji was pushed to his limit, he took a deep pierce to his shoulder and another to his thigh.
"Well," the Oni sneered, pressing his advantage. "If I kill you here, this boy dies too. Then I can return to my true form and become Supreme."
The Oni pulled back, aiming his sword like a javelin. He launched it with the force of a lightning bolt.
Renji raised his energy blade to block. The pressure was catastrophic. His own sword bent, then shattered into light. The red blade punched through his defense and pierced straight through his chest.
Renji spat a mouthful of blood, his knees buckling. The Oni extended his hand, commanding the sword to retrieve itself from Renji's body.
Renji grabbed the blade before it could move.
"Who do you think you are?" Renji growled, blood coating his teeth as he laughed. He gripped the red sword with both hands, refusing to let go. His aura exploded outward, a shockwave so violent it hurled the Oni host backward into the far wall.
The Demon King lost his connection to the weapon. Renji saw his window.
"Now!"
[VITAL POINT IDENTIFIED: THE HEAD.]
Renji laughed, a broken, desperate sound, and sprinted forward. The Oni was already chanting, trying to initiate the absorption ritual.
Just as the spell reached its crescendo, Renji spun. He threw the stolen red sword in a perfect, lethal circular arc.
It sliced clean through the Oni's neck.
"No! No! Impossible!" the severed head screamed as it fell.
The head hit the floor, but the eyes remained open, burning with malice. The Oni smiled even in death.
"This is not my real body," the head whispered, the voice fading. "You may have killed this vessel, but you will not survive when I descend in my true form to claim your world. I will come after you, Mortal King, and I will destroy you!"
With a final scream, the body and head dissolved into nothingness.
Renji stood alone, clutching his wounded chest, his breath coming in ragged gasps.
"If I barely managed to kill him in a fake body," Renji thought, dread pooling in his stomach, "what will happen when he comes in his real form?"
He looked around the silent hall. "The Demon King... does that mean we'll be attacked by entities from other dimensions soon?"
[BEHIND YOU.]
Renji spun around. A thin, pulsating blue line, looking almost alive and harmless, extended from the glowing body of the Abyss Lord. Renji, exhausted and off-guard, reached out and brushed it with his fingers.
The energy coil instantly lashed out, wrapping around his wrist and yanking him violently toward the altar.
The entire room lit up. The stone sculptures of monks lining the walls began to glow, their eyes opening in unison. A deep, resonant chanting filled the air, speaking a language older than time:
"Omne quod fuit, omne quod erit, nunc in unum confluit. Abyssus vocat regem suum." (All that was, all that will be, now flows into one. The Abyss calls its King.)
The chanting grew louder, drowning out Renji's thoughts. He couldn't feel his body anymore.
His vision shifted. He was standing in a vast, black void. Next to him stood a figure of impossible presence, the Abyss Lord. The ancient entity walked closer and nodded gracefully.
"I know why I chose you as my descendant," the Lord spoke, his voice echoing from everywhere at once. "You are a true Mortal King, willing to sacrifice everything to save your world."
Renji bowed instinctively. The Lord reached out and placed a hand on Renji's head.
"I have waited for eons. Now, you shall receive my blessings, my power, my System, and my Soul. All shall be granted."
Energy of every conceivable color flooded into Renji. It wasn't just power; it was knowledge, history, and absolute authority.
Renji screamed as his very soul was rewritten to accommodate the influx.
"I believe in you, Renji Kurozawa. Promise me you will use this power for what is right."
Renji forced himself to speak through the agony. "I promise."
The Abyss Lord released the last of his essence and vanished into light.
Renji snapped back to reality. His body was floating, wreathed in a terrifying aura of green, purple, and blue. The power was too great to contain, it exploded upward, a pillar of light shooting straight into the sky, piercing the dimensional veil to announce the arrival of a new King.
[SYSTEM REBOOT INITIATED.]
[MERGING NECROMANCER CLASS...]
[MERGING VOIDMANCER CLASS...]
[COMPLETE.]
[NEW CLASS: THE ABYSS MONARCH (RANK: SUPREME LORD)]
-------
Dimension of the Sages: Aetheria
The shockwave of the new King's power rippled through the golden realm of Aetheria, alerting the Council of Sages.
"Hmm. The prophecy is true," Sage Valerius murmured, his eyes narrowing. "Even the Demon King couldn't stop it. We must find this Mortal King and destroy him before his influence spreads."
--------
Dimension of the Lords: Terra-Prime
In the realm of the High Lords, the sky turned a deep violet as the signal reached them. Scores of winged Lords took to the air, witnessing the birth of a rival.
"The prophecy has begun," High Lord Malakar announced, watching the rift in the sky. "It says that when the Mortal King claims the power of the Abyss Lord, no one can defeat him—not even the Demon King.
We must prepare."
------
Dimension of Gehenna: The Demon Throne
Lord Oni gasped, waking violently from his possession trance. He was back in his massive, true body, sitting on his obsidian throne.
"No. No! This cannot be happening!" he roared, slamming his fist onto the armrest, cracking the stone. "I was defeated by a mere mortal!"
He sensed the shift in the cosmic balance. Renji had already absorbed the power.
"I will come after you, Mortal King," Oni whispered, his eyes burning with hatred.
"Lord of all Mortals."