The battle began with shattering blood.
The very air trembled with the cries of agony as the low-ranked shadow-bound tore through the battlefield like a storm of living nightmares. The sound of ripping flesh echoed in every direction, a sickening symphony that clawed at the hunters' ears. What had once been a disciplined formation was now a maelstrom of screams and steel. Men and women alike were thrown to the ground, their weapons falling from blood-slicked hands as their bodies were torn apart. Pools of crimson spread across the cavern floor, reflecting the hellish scene above.
These monsters were beyond anything the lower ranks could handle. Even C- to B-ranked hunters were struggling to hold their ground against the overwhelming tide.
Nobody knew why these creatures had such terrifying strength. Even the upper ranks—seasoned warriors who had survived countless raids—were slowly being pushed back. The cave stank of iron and fear, its shadows stretching unnaturally, as though the cavern itself had turned hostile.
At the back of the cavern, Yume and Captain Haru fought with grim determination, but their gazes kept flicking to the massive gate looming behind them.
The gate had called Ren.
It had glowed with a strange, pulsing light before pulling him in, as though obeying some ancient will. The heavy stone doors had slammed shut behind him, sealing him away. Since that moment, not a sound had come from within.
Inside the gate, Ren stood perfectly still, his breath fogging in the air.
The space around him was unlike anything he had ever seen—an endless void, black yet strangely weightless, as though the world had been hollowed out. The ground beneath him was smooth as obsidian, and not a single sound stirred the air.
Until—
"Welcome, Ninth Sovereign of Shadows."
The voice rolled like distant thunder, echoing from every direction.
Ren stiffened. Me? His own voice sounded small, swallowed by the vast emptiness.
"Yes. You."
Suddenly, eight colossal thrones materialized before him. Each was carved from dark stone that pulsed faintly with life, like a heartbeat. Seated atop them were eight figures, each cloaked in a unique shade of shadow—midnight, ash, storm-gray, smoke. Their mere presence pressed against Ren's chest like a physical weight, yet there was no malice in their gaze—only reverence.
"Welcome, Ren Akatsuki," they spoke as one, their combined voices shaking the very air. "We, the Eight Sovereigns, welcome our Ninth Sovereign—the one destined to defeat the Shadow Demon."
Ren's heart thudded violently. Confusion, fear, awe—everything hit him at once. His lips trembled as he stammered, "Why… why am I here? I'm nothing—why me?"
The First Sovereign's voice cut through the void like a steady drumbeat:
"Ren Akatsuki, hear the truth mankind was never meant to know. At the end of the prophecy lies a hidden line, never spoken aloud: The Ninth Sovereign shall be born among humans, despised, cast aside, yet tested to see whether he will remain loyal to mankind. Even we, the Sovereigns, could not endure the pain you have suffered. Yet you remained loyal. For that, we thank you—from the bottom of our hearts."
Ren's chest ached with the weight of the words. Loyal to mankind? Was that what his suffering had been for?
The Second Sovereign leaned forward, his form glowing faintly.
"You have seen the darkness of humans—greed, hatred, selfishness. They burned your village, cast you out, called you worthless. Anyone else would have sought revenge. But you endured. You forgave. You still chose to fight for them. That is why you were chosen."
Ren's throat tightened. For the first time, he felt truly seen—beyond Yume, beyond his master, beyond Captain Haru.
"But I'm just a low-ranked hunter," Ren said, voice shaking. "There are S-ranks—stronger, more capable—why not them?"
The Fifth Sovereign's voice was calm, almost proud:
"They stood before the gate, yes. But they lacked what you carry—the will that refuses to break. Others let jealousy and greed consume them. You, Ren Akatsuki, are different."
Then the First Sovereign's voice rose like thunder:
"From this moment forth, Ren Akatsuki shall inherit the Black Heart as the Ninth Sovereign!"
Ren's eyes widened. "The… Black Heart?"
The Sixth Sovereign's whisper was like wind through a graveyard:
"It is our core power. For now, it will remain separate. But when the time comes, it will merge with you and grant you absolute strength. Even now, you may temporarily rise to Rank A."
Ren's breath caught. From F-rank to A-rank? It sounded impossible.
"What must I do?" he asked, desperate. "How do I live up to this title?"
The Second Sovereign's reply was firm but kind:
"You may not feel worthy now. But your resolve to protect others proves that you will become the strongest. When the Black Heart fully merges with you, you will carry the strength of the Sovereign of Shadows."
Ren clenched his fists until his knuckles whitened.
"Then I'm ready," he said at last, his voice like steel. "I'll fight alongside you. I'll protect mankind—and those I care about."
The Eight Sovereigns stood as one, towering like mountains, and their voices thundered:
"Behold! The Ninth Sovereign, Ren Akatsuki! Now, receive the Black Heart!"
A blinding surge of light erupted, dark energy spiraling around Ren like a living storm. His breath hitched as raw power flooded his body, burning and freezing him all at once. His eyes turned a pure, glowing white, and shadows swarmed around him until his figure became a silhouette of living darkness.
Back in the cave, Captain Haru's team was falling apart. Hunters lay scattered, bleeding, their faces pale.
Why are these things here? Haru's mind burned. Even an S-rank Shadow-Bound can't hold them off forever!
"Everyone, fall back!" Yume's voice rang over the chaos. "Low-ranks, get out of here NOW!"
Arata Nozomi grabbed the survivors and dragged them toward the exit.
But then—two shadows lunged.
Their claws tore into Yume's back before anyone could react, blood spraying in a scarlet arc.
"MISS YUME!" Haru roared, but more monsters swarmed between them.
"Arata!" Haru shouted. "Take them out! GO!"
Arata hesitated, then obeyed, dragging the screaming survivors away.
Yume slumped against the wall, blood running down her back in a river. Her vision blurred, breath shallow.
So this is how it ends…? she thought bitterly. I never even told him how I felt…
The monsters closed in, claws raised.
And then—
The gate exploded open.
A shockwave ripped through the cave, shaking the ground. Dark smoke spilled out, swallowing the cavern like night itself. The temperature plummeted until every breath came out as mist.
The monsters froze. Their snarls turned to whimpers. One by one, they backed away from the gate's glow.
A figure stepped out.
Ren.
He walked slowly, each step echoing like a drumbeat. His aura pressed on every soul in the cave like an invisible hand. Hunters dropped to their knees, gasping for breath. The very air bent around him as shadows coiled and slithered across the walls.
His glowing eyes cut through the darkness, cold and merciless.
In an instant, he struck down the creature standing over Yume. It disintegrated into black ash before it could scream.
Ren knelt beside Yume, shadows curling protectively around them. He placed a hand over her wound, and darkness enveloped her like silk. Flesh knitted together, blood vanished, pain faded.
Yume gasped, staring at him with wide, terrified eyes.
"Who are you…?" she whispered. "What happened to Ren?"
But he didn't answer. His gaze turned to the horde of monsters, burning with an unearthly rage.
"Wait for your turn to die," he said, his voice warped, layered with power.
He raised his hand. Shadows gathered and forged into a massive obsidian sword that crackled with dark energy.
Then he vanished.
The cave filled with screams as monsters were torn apart. Blood painted the stone walls, bones cracked, claws snapped. It was over in seconds.
Ren stood in the center, breathing hard, surrounded by silence and corpses.
Then his power shattered.
He coughed blood, his form unraveling into smoke, and collapsed.
"Ren!" Yume cried, catching him and pulling him into her lap. "What happened to you? Please… don't leave me…"
But he was unconscious.
Captain Haru reached them, face grim.
"Miss Yume," he said quietly. "He's alive. Barely. We need to get him to a hospital—now."
Haru lifted Ren in his arms and carried him out of the blood-soaked cavern.
Outside, Ichiro Zenko was waiting. His gaze hardened at the sight of the battered team.
"What happened in there?" he demanded.
"I'll explain later," Haru said, his grip tightening on Ren. "Right now, this man is fighting for his life."
They rushed him to the hospital, where doctors immediately took him into surgery. Yume stood outside the operating room, fists clenched, silently praying.
Even the organization's High-Rank Shadow-Bound, sent to investigate, returned feared. She too confirmed: the monsters inside had been beyond anything they had ever faced—yet Ren had slain them all alone.
Ichiro's suspicion grew as he confronted Haru once more.
"Tell me the truth," he said. "What exactly happened in that cave?"