Prologue: In the Depths of Darkness

“People fear the darkness, dread the unknown, and are terrified of death. The Demon King, then, is the very embodiment of their deepest fears. As the ruler of darkness and the master of the Hall of Demons, the Demon King must ensure that all understand both how to fear and how to respect him, finding a perfect balance between brute force and sweet persuasion—much like forcing a human to eat a piece of bread, then smiling as you inform them it contained half a cockroach.”
—Seprath, the 333rd Demon King

The flickering candlelight gently illuminated the dim study, casting wavering shadows across the room. In its weak glow, a young man could be seen curled up in a chair before the desk, poring over a hefty tome.

He appeared to be about sixteen or seventeen years old. His handsome face was pale and gaunt, a result of long days spent away from sunlight, and his jet-black mage’s robe draped all the way to the floor. At first glance, he seemed no different from any ordinary person. Yet the subtle horns peeking through his hair at his temples, and the vivid red of his eyes, betrayed his true nature.

He was a demon.

“Hah…”

After a while, Jayne finally closed the book before him, removed his glasses, and massaged his aching eyes. Unlike the precise, structured writing of spellbooks, the historical records of the demons were almost unreadable—dry, rambling chronicles, more reminiscent of a child’s hastily invented holiday homework than genuine history.

In some ways, even the web novels Jayne used to read were a thousand times more entertaining than this.

“Maybe, when I become Demon King, the first thing I’ll do is find a competent scribe.”

Muttering to himself, Jayne rose and stretched.

The cramped study was tidy but somewhat dilapidated, hardly surprising given that it was a cave of barely twenty square meters underground. In such a place, what sort of environment could one hope for? Except for the dank, gloomy tunnels, the monsters lurking in the dark, and the omnipresent death, there was little else.

But to Jayne, this was his only home.

“Time really does fly…”

Sighing, Jayne couldn’t help but recall the moment he first arrived in this world.

Once, he had been a renowned hacker in Earth’s digital underworld. No matter how powerful the firewall, unless a network was physically isolated, nothing could stop Jayne’s hand.

Yet even Jayne hadn’t foreseen his own downfall. For the sake of convenience, he’d written a script for one of his favorite online games, only to be promptly banned by the administrators. Dissatisfied, he had naturally hacked into the official server, intent on clearing his name. In the midst of his tampering, he ignored the thunderstorm warning outside…

As it turned out, there’s a reason we’re told not to use household electronics during a lightning storm.

Not only did Jayne’s computer end up fried, but he himself didn’t escape unscathed. When consciousness returned, he found himself emerging from an eggshell—as a demon, no less, and one of the Demon King’s heirs.

After enduring over a decade in that chaotic, hellish realm, just as he’d grown accustomed to life in the demon world, Jayne was summoned by his so-called father and, under the pretense of the Demon King succession ritual, was unceremoniously exiled to this desolate forsaken place.

That was hardly surprising—not when, of his five siblings, Jayne was by far the most unimpressive. Eldest brother Klein was the strongest contender for the throne, and even the name of his second sister, Lylisia, was enough to stop children’s cries throughout the demon realm. Even his two younger sisters were figures of fear.

Only Jayne—the third brother, or perhaps more accurately, the third son—was virtually unknown. He did nothing but bury himself in the library all day and had never accomplished anything noteworthy. His own strength was laughable, barely on par with a demon foot soldier, and compared to his well-armed siblings, Jayne’s influence was pitifully small.

He had only two followers.

No wonder he’d been abandoned in this wretched place. Otherwise, before he’d even finished packing his dungeon, he’d likely have been reduced to fertilizer in the depths and the butt of yet another demonfolk joke that would never die.

The so-called Demon King succession ritual was, in truth, simple. Each of the five heirs chose a region, built their own “Dark Fortress,” expanded their power, and in the end, whoever emerged victorious would become the next Demon King.

Direct and brutal. No human-like ceremonies, no elections, no canvassing or backroom deals, no need to appear on television to present one’s political platform. The strongest ruled, and in the demon world, that principle was law—almost sacred truth.

“But at least… I’m finally free.”

Staring into the void before him, Jayne pushed his glasses up the bridge of his nose, a glint flashing in his crimson eyes. For at this very moment, lines of data were appearing before him.

[Dungeon Construction System]
[Lord: Jayne]
[Level: 1]
[Development Progress: 355/1200]
[Resources: Ore (50), Quicksilver (20), Gems (15), Crystal (70), Gold (1520)]
[Subordinates: 6]
[Buildings: Dungeon Heart (You feel your heart pounding fiercely; it is proof that you live, and a countdown to your demise. Everything depends on how you choose to court death) — Max HP +100]
[Building: Study (Here lie the secrets of history, the laws of the world, and explosive issues of Playdemon Magazine. It’s up to you to unlock their mysteries) — Magic Amplification +3, Mana Regeneration +10]
[Building: Bedroom (When lying in a soft bed to ease your fatigue, don’t forget it’s for more than just sleep—it’s closely tied to the secrets of this world’s survival) — Health Regeneration +10, Max Stamina +10]
[Building: Nest (Even a slave deserves rights. Only when they taste the benefits of social security will they devote themselves more wholeheartedly to their employer) — Loyalty +1]
[Magic Research (LV1): No research target]
[Blueprints (LV1): No blueprints]

“At last, I’ve made it through…”

Gazing at the floating panel, Jayne sighed with profound relief.

Indeed, after crossing into this world, Jayne had inexplicably gained this system. It was, in fact, no stranger to him—an exact replica of the one in his favorite online game. For reasons unknown, it had fused with his soul and traveled with him across worlds.

Unfortunately, while having such a system should have been a boon, it was useless at first. To his frustration, he discovered that unless he first established his dungeon, the system was completely sealed. No matter how much knowledge he acquired, it was impossible to convert it into power. Even if he could recite spell incantations with perfect precision, he still couldn’t cast a single powerful spell.

Meanwhile, as his siblings progressed by leaps and bounds, as if stuffed with every cheat code imaginable, Jayne could only idle away his days in the library with his inert Level 1 dungeon system. No wonder his strength was so abysmal that even the demonfolk pitied him.

After all, what use are a hundred legendary spells to a character who’s been stuck at Level 1 since birth, with no increase in HP or MP? If you can’t cast them, it’s all in vain.

Now, however, his ordeal was at an end. Exiled to this godforsaken place, Jayne could finally activate his dungeon and claim the power that should have been his.

Admittedly, this newborn dungeon was pathetically weak. Aside from Jayne, the nominal lord, there was only his ever-present adjutant and five goblins he had summoned upon arriving. Such a dungeon would be easy prey for any half-decent party of adventurers.

Luckily, this was a no-man’s land, and Jayne’s dungeon lay several hundred meters underground. No bored adventuring party would bother to explore this far. Even so, this place was not without its dangers.

A sudden, thunderous rumble echoed from afar. The ground began to tremble, sending dust cascading from the ceiling. Almost at the same moment, there was a knock at the door.

“My apologies for disturbing you, Master.”

The study door slowly opened, and a slender, petite figure glided into the room like a ghost. She was a girl of about fourteen or fifteen, with soft golden hair and delicate features, her gentle smile as refined and soothing as a spring breeze. She wore a luxurious black dress that gave her the appearance of an aristocratic young lady. But the red eyes, triangular ears, and pale skin marked her as anything but ordinary.

“What is it now?”

Closing the book at his side, Jayne looked at his adjutant with resigned curiosity.

“It’s the southern passage, Master. The goblins have collapsed it again. Approximately one-third of the dungeon has been damaged this time. What are your orders?”

…

It seemed a capable architect was indeed the most essential part of any dungeon.