The Spiritual World—an existence far removed from mortal comprehension—was known by only one name among those who feared it: the Realm of the Demons.
Here, amidst an atmosphere choked with ancient magic and oppressive shadows, reigned the immortal and merciless Demon King—Lord Rusty.
In this dark dimension, demons did not live freely. They served. They obeyed. They bowed before Rusty's unfathomable power. Every demon, no matter how monstrous or mighty, was but a pawn in the eyes of the King.
The demons were classified by Lord Rusty himself, divided according to strict metrics: Spiritual Power (SP), skill proficiency, knowledge capacity, intelligence, potential, and more. Through these harsh standards, they were ranked from D-Rank to S-Rank, forming a strict and ruthless hierarchy.
Lord Rusty himself was unranked. As the absolute monarch, he stood beyond classification.
Over 500 demons filled the D-Rank—the lowest rung of this brutal society. Despite their overwhelming power compared to humans, D-Rank demons were mere insects before the higher ranks. C-Rank demons numbered around 350, each stronger and more disciplined than the tier below. The B-Rank, composed of a select 100, were veterans of countless battles, respected and feared. The A-Rank, numbering about 50, were considered elite—commanders, generals, the mightiest beneath the top.
And then there were the S-Ranks.
Only four demons had ever reached this level across millions of years.
Among them was Zedzy—a cunning, calculating entity of immense intellect. His mind was sharper than any blade, his knowledge deeper than any ocean. Though not the strongest in raw combat, he was respected, feared, and most dangerously—underestimated.
The other two notable S-Rank demons were Rusty's adopted children:
Zephyr, the elder son, was a warrior without equal—second only to Lord Rusty in sheer physical might. A tactical genius, Zephyr's instincts in battle were matched only by his ability to deduce complex threats in moments. His cold, calculating nature made him the embodiment of discipline and loyalty.
Velmira, the younger daughter, was less refined in combat and intelligence but possessed vast reserves of SP and almost inhuman stamina. Her loyalty to Rusty bordered on fanaticism—not out of blind faith, but gratitude. For Lord Rusty had raised her, trained her, and shaped her into what she was. She owed him everything.
The reason Zephyr and Velmira alone were honored as Rusty's children was not affection, for the Demon King harbored no such weakness. It was loyalty. Of the four S-Rank demons, they alone would willingly die for him, even knowing Rusty would not hesitate to sacrifice them.
In the Realm of Demons, such loyalty was rare. And therefore, precious.
Each S-Rank demon commanded their own castle, their own armies, and their own A-Rank elites. Below them, the B, C, and D-Rank demons lived in vast sectors of the Spiritual World, outside the fortified lands of their masters. Only when summoned for training or war did they enter the great castles of the S-Rank generals.
The A-Ranks, meanwhile, lived within these castles as permanent retainers—training under their masters, and themselves training the lower ranks in a cruel, endless cycle of power and obedience.
Lord Rusty himself resided in the legendary fortress known as Blackhold—a citadel so massive and ancient, none but the S-Rank demons had ever seen it from within. Its twisted spires reached beyond the storm-wracked sky, and its walls pulsed with cursed energy. Merely approaching it could break the will of a lesser demon.
Rusty never left it. He didn't need to.
He was everywhere—through his SP alone. So overwhelming was his power that he constantly suppressed it. If unleashed, even a fraction of it could obliterate legions of his own kin.
The S-Rank demons, by contrast, each lived in their own castles called Nightspires. They were fortresses of distinct architecture, shaped by the personality and essence of their masters.
And in one such Nightspire, nestled within a field of eternal darkness, rested the brilliant and scheming Zedzy.
He sat in solitude, draped in a cloak of shadowed silk, a spectral flame hovering above his palm as he pondered his next move.
His goals were his own—hidden, dangerous, and calculated. Over the years, he had ventured into the human world more than once. Each visit had been secret, meticulously planned, and devoid of trace. Whatever his motives, they were known to none but him.
He murmured to himself, eyes glowing faintly beneath his hood.
"It's nearly time. A few more years... and the pieces will be in place."
But then, without warning—
A voice echoed in his mind.
"Come to Blackhold. Immediately."
Zedzy's eyes widened.
It was Rusty's voice.
He felt it. Not the words, but the fury behind them.
Rusty rarely summoned anyone. And when he did, it was never with anger unless something had gone terribly wrong.
Zedzy stood. Instinctively, his mind sharpened like a blade. He analyzed every recent move he had made, every shadow he had crept through, every spell he had cast.
Did he find out about me?
No. No, impossible. I covered every trace. Burned every path. I was invisible.
But doubt, like a crack in marble, had already begun to form.
Zedzy vanished in a streak of dark light, warping through the abyssal sky until the towering gates of Blackhold loomed before him. The sheer presence of the castle churned the air like a tempest. Every second spent here without Rusty's consent would be suicidal for a lower demon. But Zedzy... Zedzy was S-Rank.
He passed through the gates unchallenged.
Zedzy knelt, his head bowed low, the grand throne room silent but for the crackling of the flames that lined the obsidian pillars. At the far end of the room, seated upon a throne carved from the bones of fallen kings and veiled in shadow, was the Demon Lord himself—Rusty. His crimson eyes burned with barely restrained fury.
Zedzy raised his head, forcing a smile despite the tension in his chest.
"Lord Rusty," he said, voice steady, "I am at your service."
But the response was not one of welcome.
Rusty's voice rumbled through the hall like thunder over a broken battlefield. "Why did you go to the human world?"
The silence that followed was deafening.
Zedzy froze. His eyes widened.
"Huh?"
Panic bloomed in his chest. How? How does he know? He had been meticulous, careful—every portal sealed, every witness silenced. Not a trace, not a whisper should have reached the throne room.
And yet…
Zedzy's breath hitched. Slowly, he turned his head to the left, as if compelled by some invisible force. His blood ran cold.
There, leaning casually against one of the pillars, was a demon dressed in human attire—a dark suit that clung elegantly to his tall, lean frame. He was strikingly handsome, with silver hair that shimmered like moonlight and eyes as sharp and unreadable as a frozen lake. His smirk was the kind that could slice a man in two without lifting a finger.
It was him.
Zephyr.
The strongest demon in the Underworld after Rusty himself.
Rusty's adopted son.
And Zedzy's worst nightmare.
"Of course," Zedzy whispered to himself, dread filling his veins like poison. "It was him…"
Zephyr's smirk widened, as though he had heard Zedzy's thoughts. He tilted his head, feigning innocence, but his eyes glittered with amusement and malice. His presence radiated superiority, elegance—and something far more dangerous: absolute control.
Mocking me... he's mocking me.
Zedzy clenched his fists, forcing himself not to rise, not to retaliate. He knew what that would mean. Not in front of Rusty. Not here.
Zephyr took a step forward, his voice soft, melodic—infuriating. "Oh? You didn't think I'd notice your little excursion, Zedzy? You underestimate me."
Zedzy's eyes flickered with rage. No, I didn't underestimate you. I just hoped you'd stay out of my business.
But he didn't speak. Not yet.
Because before him sat the Demon Lord. And the Demon Lord had yet to pass judgment.