The Strongest Demon King Can't Conquer the World Because His Subordinates Are Total Disasters
Diabolos, the world's strongest demon king, should be able to conquer all continents in a single night with his overwhelming power. But his subordinates' imagination-defying incompetence keeps sabotaging every world conquest plan.
In Episode 1, the demon king's castle gathers an assortment of executives who are supposedly quite competent—yet everything they touch goes sideways. The military commander forgets battle plans immediately. The strategist loses critical documents. The Hell Duke bullie
The Strongest Demon King Can't Conquer the World Because His Subordinates Are Total Disasters - Source, mirror writing, and a single ray of light
Morning had come to the Hall of Judgment.
The defense plan that Yuki and Diabolos had worked out together the night before lay stacked in front of him. They'd overlaid map after map, double-checked the numbers, and kept talking even as the black rock tea from midnight became three cups. Thinking back on that night, today should finally move things forward—or so it was supposed to.
"Then, let us begin the meeting."
Diabolos spoke.
His voice was quiet. Always quiet. Two hundred forty years of exhaustion nested in its depths, but his face showed nothing.
Five chairs lined the Hall of Judgment. Lava flowed down the walls, serving as lighting. To Diabolos's left lay the plan they'd finished last night. A little to his right sat Yuki. Her silver hair caught the lava's orange glow, and her pale blue eyes faced forward. Her expression was calm as always, but the way the corners of her documents were perfectly aligned showed that last night's work continued here.
The remaining two seats held Dolkias and Zephador.
"First, then, the distribution of the defense plan."
Dolkias Melve stood up.
A lanky man with thin fingers. Everything about him screamed paperwork specialist, and today his eyes were particularly busy behind his gaze. He began handing out the stack of documents he'd been holding to everyone. His face said: This time, everything is perfect.
Diabolos opened the first page.
He could read it.
A faint sense of relief began to form.
The second page. For some reason, a sauce stain had spread across it, and half the text had dissolved.
The third page. Sauce.
The fourth page. Sauce, and traces of some unidentifiable food ingredient in one spot.
The fifth page. The pages were stuck together and wouldn't open. The sixth page was the same.
Diabolos slowly set the documents down on the desk.
"...Your documents..."
There was a beat of silence.
"Why are they always integrated with food?"
"Last night, while I was re-reading and eating a late-night snack, my chopsticks—"
"Stop."
"But the readable portions are actually extremely excellent content—"
Yuki raised her hand.
"Please indicate with your finger what percentage of the total is readable."
Dolkias thought for a moment, then used his fingers to show.
Roughly thirty percent.
A faint silence fell over the Hall of Judgment. Only the low sound of lava flowing down the walls echoed.
The wrinkle between Diabolos's brows deepened by one line. A blood vessel quietly snapped—metaphorically speaking, in the conference room.
"Rewrite it."
"I'll be right back!"
Dolkias left the room clutching the documents. His footsteps faded away.
The door closed.
---
"Then allow me to present an alternative."
Zephador Glintz stood up.
A man bearing the title of Hell Duke. Large-framed, dressed in black formal wear, he held his chin high with movements that carried a theatrical flair. His crimson eyes burned with confidence, and Diabolos knew from experience that this was the sign something was about to begin.
He arranged his posture to listen with a faint glimmer of hope. Today, please. Just one decent proposal.
"As a countermeasure against the Scarlet Iron Holy Pilgrimage, I believe we should first fundamentally improve the morale of the demon king's army."
The Holy Pilgrimage—formal name, Turba Feroalba. An armed knight order formed four years ago on the central continent of Seriola, led by former mercenary captain Orvan Drexia, comprising a total of six thousand two hundred members. They proclaimed "the eradication of demons and complete defense of human territory," and from their fortress city of Cardonas, they had publicly declared war on the demon king's domain.
Facing such an organization, improving morale. The direction wasn't bad.
"Specifically," Diabolos prompted.
"Further strengthening of punishment standards."
Diabolos's thoughts stopped for one second.
"...Weren't you saying the same thing last week?"
"This week I've made improvements. Last week's proposal was three days in the brig for five minutes late, but this week's proposal is five days in the brig for three minutes late."
Zephador puffed out his chest. Proudly.
"...Improvement typically refers to something becoming better."
"With greater strictness, greater discipline—"
"Please confirm the current number of operational soldiers."
Yuki cut in quietly.
Zephador began counting on his fingers. A long silence followed. Outside the window, the wind of Morg Zaren howled. The distant, low rumble of the active volcano Gromud Caldera could be faintly heard.
"...By rough estimate, those with high morale number fourteen."
"We need a minimum of eight hundred for castle security."
A gap fell between them.
"If we discipline those eight hundred—"
"There are no more."
"Then we recruit new—"
"The rumors of punishment have spread. We have zero volunteers."
Zephador opened his mouth. Closed it. Opened it again. Closed it again. His crimson eyes swam through the air at an odd angle.
"...Is there a possibility that soldiers who underwent punishment might return with improved morale?"
"Many soldiers who entered the brig have gone missing, so the premise of them returning doesn't hold."
Silence.
For the first time, Zephador's face showed he was beginning to dimly understand that his measures had backfired. Yet still, something seemed to catch in his throat, his mouth moving slightly. The conviction that punishment was right still sat in the depths of his eyes.
The wrinkle between Diabolos's brows deepened further. Several more blood vessels quietly snapped.
"Be silent."
A low, short voice.
Zephador sat down in his chair.
---
"Yuki. You speak."
Diabolos said it. Just that, in the silence that followed his command for everyone to shut up.
Yuki stood.
She spread out documents. Placed a map on the table. The lines and numbers the two of them had drawn last night became sharp and clear in the lava's light. Yuki's voice was matter-of-fact, almost devoid of emotional inflection. That very quality gave each word density.
"There are two pillars."
"One—the weakness of the Scarlet Iron Holy Pilgrimage lies in supply line management. Orvan Drexia, being a former mercenary, is skilled in combat command, but lacks experience managing long-term supplies for units exceeding six thousand. If we cut off the sea route through the Cleft Sea—the strait between Morg Zaren and Seriola—and use the Gorge Canyon of the Iron-Back Mountains to isolate the land supply convoys, even a large army cannot move."
Diabolos ran his pen across the map. Drew a line along the sea route. Confirmed the canyon's position.
"Two—we utilize Morg Zaren's volcanic terrain as defensive positions. The area around Gromud Caldera has the highest concentration of source veins, maximizing the output of your majesty's dark flame sorcery. Additionally, if we choose the lava plains as the main battlefield, the Holy Pilgrimage's holy-blessed silver weapons—materials that temporarily sever a demon's source vein connection—may not achieve their full performance in high-temperature environments."
"The plan is logical."
Diabolos said it. Unusually, straightforwardly.
Yuki paused for a moment. A pause as if choosing her next words.
The problem surfaced immediately after.
"Who will you entrust with field command of the skirmish tactics?"
The room went quiet.
She looked at Zephador. Fourteen subordinates. The canyon skirmish required at least several hundred deployed across dispersed positions.
Dolkias had gone to rewrite. Sending him to the field would guarantee lost documents. That was a fact derived from empirical experience.
The Black Fang Round Table had seven seats. Currently five. The two vacant positions had never been filled.
Diabolos placed his fingers on the desk.
"...In other words..."
There was a beat.
"There is not a single commander in this castle capable of executing this plan."
Yuki's eyes lowered for just a moment.
There was no response. There was no need for one. There was no basis for denial.
Something in Diabolos quietly sank. He remembered that night two hundred forty years ago, when he'd faced the trial seat of the abyss alone. When the murky current of source veins burned through his entire body and his flesh began to scatter into mist, no one had extended a hand to him. He'd survived because only his will had sustained him.
That sensation returned now.
In the end, he had to do it himself. It had always been that way. Would it always be?
Two hundred forty years, the same conclusion returning to the same place again—
"There is one piece of good news."
Yuki opened her mouth.
Her voice was quiet. But the air in the Hall of Judgment shifted slightly. Zephador looked up.
Yuki pulled a single document from her pocket. A resume. The fold lines were perfectly aligned.
"There is a strategist who graduated first in her class from Orblesse Military Academy, the prestigious military school of Seriola. The hypothetical invasion plan she devised during her studies was evaluated by the teaching staff as 'of a completeness that should be adopted as a textbook.'"
Diabolos stopped his pen.
"Twenty years old. Name is Gareth Varoon. She has applied to volunteer for the demon king's army as the inaugural holder of a new staff position—Strategus. She is scheduled to arrive tomorrow."
"...First in her class."
"Yes."
"She devised a plan that became a textbook."
"Yes."
"In her twenties."
"Yes."
Diabolos leaned forward.
Two hundred forty years. He had never felt the length of that time—waiting for a capable subordinate—as acutely as he did in this moment. He'd kept everything running alone all this time, between Zephador's rampant punishment abuse and Dolkias's sauce-covered documents.
Finally—
"A genius strategist!"
The door opened and Dolkias came back. Before anyone could question why he'd returned from rewriting, he'd caught the conversation with sharp ears. His eyes gleamed.
"I want to write the plan with her! A new comrade!!"
"We'll need to explain the punishment regulations to her first."
Zephador crossed his arms with a serious expression.
Diabolos glanced at both of them. He judged that commenting would be pointless and turned his gaze back to Yuki.
"Prepare everything."
"Yes."
Yuki answered briefly, but her eyes remained lowered on the resume in her hands.
Her gaze stopped on one line.
Manual compliance rate: 100 percent.
Successful operations through field judgment: 0 cases.
Yuki's brows furrowed, just slightly.
No one noticed that expression. Dolkias was distributing new documents, Zephador was writing punishment regulations in his notebook, and Diabolos had returned his gaze to the map.
"Let us conclude the meeting."
Diabolos stood. Something mixed into his voice that wasn't quite like him. Not heaviness—something closer to anticipation.
"Prepare for her arrival tomorrow. That is all."
Zephador and Dolkias left the room. Their footsteps faded. Faint voices of the two arguing could be heard from the corridor, but it no longer mattered.
Yuki remained alone in the Hall of Judgment.
In the quiet flow of lava, Yuki picked up the resume again.
Manual compliance rate: 100 percent. Successful operations through field judgment: 0 cases.
The same letters remained no matter how many times she read them.
Gareth Varoon. Twenty years old. First in her class. A genius with a plan that became a textbook.
The numbers were correct. The achievements were real.
But the battlefield was not a classroom. There would inevitably come moments when manuals didn't apply. How this person would move in those moments—the resume contained not a single record of that.
Yuki quietly closed the documents in the file.
In the orange light of the Hall of Judgment, her silver hair swayed slowly.