Kuro's footsteps echoed softly against the damp, ancient stone as he continued deeper into the labyrinth. The scent of blood and charred flesh still lingered in the air, a grim reminder of the battle he had just survived. His muscles throbbed with every step, his breathing heavy, and his mana was dangerously low—barely enough to summon even a single shadow soldier now.
Despite this, Kuro didn't stop.
His eyes, sharp and alert, scanned every inch of the passage ahead. The victory against those monstrous creatures had not just left him physically exhausted—it had raised questions. Why had those monsters acted so differently? Why had the leader seemed intelligent? Calculated?
And more importantly… why did it feel like they had been guarding something?
The corridor narrowed, forcing Kuro to walk in single file with his three remaining shadow skeletons. The third one, the silver-armored warrior, moved in front as a vanguard. The other two flanked Kuro, guarding his sides. Their bodies were scarred and chipped, but their loyalty never wavered.
Minutes passed in silence, the tension thick enough to choke on.
Then the corridor opened up into a chamber—a massive, dome-shaped room with cracked marble pillars lining the edges. A faint blue light shimmered from above, casting eerie reflections off the slick, wet floor. The air was cold, unnaturally so, and every breath Kuro took felt like inhaling frost.
At the center of the room stood a pedestal, and atop it… was a crystal.
Not just any crystal. This one radiated power. Dark energy pulsed from it in waves, making the hairs on Kuro's arms stand on end. It was obsidian black with streaks of deep violet running through it like veins. Even with his limited mana sense, he could tell this thing wasn't just magical—it was ancient. Dangerous. Forbidden.
Kuro approached cautiously, his hand hovering near the hilt of his sword.
"What is this…?" he murmured, eyes narrowed.
One of the skeletons took a step forward, but Kuro raised a hand to stop it. "Wait. This feels like a trap."
He scanned the room again—nothing. No monsters, no hidden doors, no enchantments he could detect. And yet… the unease in his chest refused to fade. He circled the pedestal slowly, studying the strange runes etched into the floor around it.
They weren't in any language he recognized—but somehow, he understood them.
'To those who seek vengeance…' the runes pulsed faintly as if reacting to his presence. 'Offer your will, and you shall be heard.'
"Vengeance…" Kuro whispered.
He clenched his fists. Visions of the heroes who had betrayed him—their laughter, their cruelty, the way they had left him to die—flashed through his mind like a storm. Rage surged within him, hot and heavy.
He stepped forward and placed a hand on the crystal.
Instantly, the world around him shattered.
---
He was no longer in the labyrinth.
The walls, the cold, the shadows—gone.
Instead, Kuro found himself standing in an endless void of stars. A black sea of nothingness dotted with constellations, each one pulsing with light. Before him floated a figure, cloaked in shadow, its form shifting constantly between humanoid and monstrous.
"You touched the Echo Crystal," the entity spoke, its voice layered and distorted, like a hundred voices speaking at once. "Few survive the trial to reach this place. Fewer still are worthy of my power."
Kuro stood tall. "Who… what are you?"
"I am the Will of the Labyrinth. The guardian of secrets long forgotten. And you—Kuro—bear the mark of the accursed."
"The curse isn't real," Kuro said. "It was a lie to abandon me."
"Yes. But lies often hide truths."
Before Kuro could ask what that meant, the entity continued.
"You seek vengeance. You wish to destroy those who wronged you. But power comes at a cost. If you accept the gift I offer, you will walk a path from which there is no return."
Kuro's jaw tightened. "I've already been abandoned. Betrayed. Left for dead. There's no path back for me. Only forward."
"Then kneel, Kuro. Accept the mark of the Undying General."
The space before him split open, revealing a swirling vortex of black and crimson energy. Kuro hesitated only for a second—then he stepped forward and plunged his hand into the vortex.
Agony ripped through his body.
He screamed as tendrils of dark energy wrapped around him, burrowing into his skin, his soul. His vision blurred, bones cracked, and every nerve lit up with fire. His shadow writhed beneath him, stretching, growing, as if it too were evolving.
Then, silence.
Kuro collapsed to one knee, panting, sweat pouring from his face.
When he opened his eyes, the void was gone.
---
He was back in the chamber.
The crystal was gone. In its place was a black mark, now etched into his right palm—a swirling symbol of a skull surrounded by skeletal wings. His mana pulsed erratically, stronger than before. He could feel it—new power coursing through him. His shadow skeletons turned toward him in unison, then dropped to one knee as if sensing the change.
[Skill Acquired: Shadow Dominion - Rank E]
[Title Acquired: Undying General]
[Unique Passive Unlocked: Deathlink]
Kuro's eyes widened as the system messages scrolled across his vision.
"What the hell…?" he whispered, reading them carefully.
—
Shadow Dominion – Rank E:
Allows the summoning and control of an additional 5 shadow soldiers. Future evolutions increase this limit. All shadow soldiers summoned by the user gain increased movement speed and agility based on the user's INT stat.
Undying General (Title):
Your undead soldiers now fight harder when you are in danger. Increases all undead combat stats by 10% when HP drops below 50%. Reduces MP cost of summoning by 10%.
Deathlink (Passive):
When a shadow soldier dies, 5% of its remaining energy is transferred to the user as HP and MP. Effect stacks with each fallen soldier.
—
Kuro let out a shaky breath.
This… this changes everything.
He turned to his skeletons. The silver-armored one tilted its head, as if sensing its master's newfound strength. He raised his hand, and instantly, five more soldiers rose from the shadows—each more refined than the original batch. They knelt before him in perfect unison.
He could feel it now. The bond between them had deepened. No longer simple puppets—they were extensions of himself.
"Let's keep moving," he said, voice cold, resolved.
---
The next corridor descended steeply, carved from darker stone than the rest. Strange, glowing roots hung from the ceiling, pulsing faintly with a sickly green light. It felt older here. Ancient.
More traps. More pressure. Stronger monsters.
But Kuro didn't falter.
He cut down a serpent made of living stone with a single strike. His shadow soldiers fought like elite warriors, faster, sharper, more coordinated. They moved like shadows, striking with lethal efficiency.
And yet, something continued to bother him.
He was stronger, yes. But it didn't feel like he was alone anymore. There was a whispering in his mind now, a voice that echoed in the silence. It wasn't hostile—but it was watching. Waiting.
A test? A guide? Or something worse?
---
After an hour of walking and fighting, Kuro reached a massive stone door. Its surface was carved with hundreds of skeletal figures kneeling before a crowned, faceless king. The same mark burned on Kuro's palm began to glow faintly, and with a low rumble, the doors parted.
Beyond them was a throne room. Ruined, dust-covered, but unmistakably regal.
And seated on the throne…
Was a corpse.
An armored figure long dead, with a crown atop its skull. Blackened bones wrapped in decayed robes. In its hands, it held a long spear—one that still shimmered with magic.
Kuro approached slowly.
The moment he stepped onto the dais, the corpse's skull turned to face him.
A single message appeared in his mind:
[Boss Battle Initiated: Guardian of the Throne – Lv. 45]
Kuro didn't blink.
He drew his sword. His skeletons took formation.
"I'm not the weakling they left behind," he said. "Let's see if you can keep up."