Chapter 1 - Failure, and Then

I was a model student.

I entered the Demon King Military Academy at the top of my class and graduated at the top as well. No other demon stood above me, and none could surpass me.

The Demon King's Guide.

I delved ever deeper into the principles established when the Demon Realm first began its expansion. And when I finally became a full-fledged Demon King and was dispatched to another dimension, that knowledge shone.

I followed the Guide more diligently than anyone. Step by step, I carried out my grand plan exactly as prescribed.

I built a tower and kidnapped a princess. I worked behind the scenes to sow strife, providing every kind of support to help the heroes grow.

Once my tower had grown beyond twenty floors, I stationed goblins on the first floor and balrogs on the nineteenth. Then I sat upon the throne at its summit and waited for the heroes.

Everything was perfect.

Everything went according to plan.

The Guide was not wrong, and at last, I had only one final step left to take.

Never did I imagine I would fail to take that final step.

Not even in my dreams had I imagined that I, a Demon King, and the Guide in which the Demon Realm placed its blind faith would be subjected to public humiliation by mere humans.

* * *

COUGH

I coughed up blood. An incomprehensible reality sometimes breeds denial.

I could not face reality. Why couldn't the black flames I took such pride in harm the heroes? Why could a hero's red blade pierce my scales, harder than any metal in the world, and burrow into my heart?

I could not understand.

"How...?"

My questions outweighed my fear of death.

I had faithfully followed the Demon King's Guide. I kidnapped princesses to turn their kingdoms' fury toward me and worked behind the scenes to earn the anger and sorrow of still more people.

Those emotions made me stronger. Most of the restrictions on my power to interfere with the dimension had been lifted, and a considerable portion of the land had been transformed into demon territory. Complete conquest was no longer a mere dream.

My next step was to help the heroes grow.

The emotions of those exceptional beings were priceless. That was why the Guide instructed us to raise them, then devour them.

Following its teachings, I had nurtured them. Now that my efforts had borne fruit, all I needed to do was sit atop my tower, savor the fully ripened heroes, and grow drunk on demonic energy.

So why was I the one lying defeated?

"How? You Demon King bastards always say that, don't you?"

The hero who had marred my grand plan gave a short chuckle, mocking me.

"I don't get it. You bring this on yourselves, so why do you always look like you can't believe it?"

"What nonsense are you...!"

"You always kidnap a princess or prince to send humans a signal. The Demon King's on the move, so you'd better stop him. How considerate can you get? Killing the king would throw the whole kingdom into chaos instead."

That was because kidnapping the king would turn their anger into greed, making them wage war against one another for the throne.

"And you always send your minions after the heroes. Handpicked to be just strong enough for us to handle, too."

Because the heroes must not die along the way. We took care not to ruin the finest of dishes.

That was what the Guide taught.

"Is that all? You send monsters whether we head for the tower or not. Know what we do then? We thank you. They might be a little dangerous, but we can handle every one of them, so we say thank you and gobble them right up. It's amazing how you send exactly the right level every time. Even my parents wouldn't be as attentive as you lot."

"And when we reach the tower? It's even better. The first floor always has weak monsters. Their level rises gradually as we climb, so we can train at just the right level for us."

The hero dipped his head in a bow and murmured, "Thank you." The sight made my insides twist with anger.

I realized something had gone wrong.

"Know what heroes call towers? A gold mine where you can grow steadily, with plenty to feast on. A heavenly treasure trove."

He whispers.

He tells me that the faith of the Demon Realm, of Demon Kings, of me, was wrong from the very beginning.

It is not Demon Kings raising heroes to devour them, he says. It is heroes toying with Demon Kings and exploiting them.

"Some heroes enter a Demon King's tower, clear everything except the summit, then leave. Why? Because it's easy. Even if we kill everything, it resets after a few months anyway. It's the best hunting ground imaginable. Oh, I guess you wouldn't know, since you Demon Kings barely interact with one another?"

A hunting ground.

My tower.

"But sometimes, that stops being satisfying. It gets stale and boring. Then we just kill the Demon King. Once you die with that baffled look on your face, it isn't long before a new Demon King and tower appear. Then it's fresh again."

A hunting ground that never disappears. How great is that?

"At least you gave us a little trouble. You were much stronger than the other Demon Kings, I'd say. Plenty of heroes fell to you. Still, you did all the same things, so the ending was inevitable."

My mind reeled.

To a Demon King, a hero was a pig to be devoured at any time. We merely raised them to fatten them up and make them tastier. That would never turn a pig into a dragon.

That was what every Demon King, every demon, believed.

And that belief had been denied at its very roots.

Heroes were not pigs. They had been dragons capable of killing Demon Kings from the start.

And Demon Kings were raising dragons that could kill them with their own hands.

No, our positions had been reversed from the beginning. The heroes were toying with the Demon Kings.

How? How could this be?

"Well, goodbye, Demon King. Thanks for everything. You've helped me make quite a name for myself as a hero. I wonder who'll come entertain us after you."

The hero laughs. The heroes laugh. Their unmistakable mockery burns itself into my eyes.

"I am...! I am a Demon King! How dare the likes of you mock me!"

"A king? Is there a king here?"

"There's a generous godfather. Who takes care of us more wholeheartedly than these Demon King bastards?"

"True. Very true."

They snickered.

Rage surged through me. I could not contain the heat that threatened to explode. So I did not.

"Even if I must die, I will not go alone."

My pierced heart was already losing its strength.

Nothing would change the fact that I would die here.

Then I would punish them before I left. I would make them pay for daring to mock a Demon King.

Even if it cost me the last of my life.

I squeezed my heart, rousing every last shred of demonic energy.

Flames surged upward, and heat shimmered.

"The bastard's trying something!"

"Cut his head off, now!"

The heroes shouted, realizing what was happening too late. They scrambled into motion. A cold blade came for my neck.

SLICE

A sting ran through my neck. My vision flipped wildly.

But it was already too late.

Through my tumbling vision, I saw my headless body collapse. My heart, pierced by the hero's sword, was swelling as it radiated black heat.

The gathered demonic energy unleashed all its firepower through my heart.

I saw the heroes desperately fleeing.

Black heat swallowed everything around me.

'Ah.'

It burns.

So this is how hot my flames are.

My past flashed before my eyes. Doubt and regret took hold.

The Guide had been wrong.

If I had known that it made heroes see Demon Kings as suckers, I would never have followed it.

If I were given one more chance...

Then I'd throw that damned Guide to the orcs.

But my regret came far too late.

My vision went black.

* * *

'...je.'

My consciousness drifted through darkness.

So I was dead. Was this the afterlife, then?

Where would I go?

'...je Dei...'

A distant voice tickled my ears, but my drowsy mind made no effort to listen.

"Berge Deias! Are you here?"

At that moment, my vision brightened. I sprang to my feet.

I was in an auditorium. Hundreds of demons were all looking at me.

What was going on?

"Berge Deias! Come forward! Quickly!"

My confusion lasted only a moment before I realized that the master of ceremonies on the stage was repeatedly calling my name.

I hurried onto the stage. An aged, worldly vampire greeted me.

"Berge Deias. This isn't like you. What's the matter with you on graduation day?"

His voice was full of concern. I inferred a great deal from his words.

Graduation day, and the scene before me.

The vampire, the chairman of the academy, pinned a red badge to my chest. It was the symbol of a Demon King, bestowed upon everyone who completed the Demon King Military Academy's course.

Only then did I understand exactly what was happening.

This was the Demon King Military Academy graduation ceremony from fifteen years ago.

I was the gifted student who had graduated at the top of the class, attracting everyone's attention.

"It's nothing, sir."

"That's a relief. Everyone at the academy, myself included, has great expectations of you."

The chairman repeated what he had said in the past, word for word.

I could not understand why I had returned to my graduation day.

But there was no denying this was an opportunity.

"Thank you. I'll do my utmost."

"Good."

The chairman patted my shoulder. Then the other cadets, including the runner-up, came onto the stage one by one.

Each received a badge.

"All graduates, please turn around."

I turned. Hundreds of demons were celebrating our graduation.

"We will now begin the oath of the graduates who are to become our newest Demon Kings."

"Our top graduate, Berge Deias, will read it on their behalf."

A hologram appeared before my eyes.

[1. A Demon King must build a tower in the world assigned to them.]

[2. A Demon King must kidnap a prince or princess.]

[3. They must sow strife from behind the scenes and leave clues that they are the mastermind.]

[4. A Demon King must provide every kind of support to help heroes grow.]

[5. Place low-level demonic creatures and monsters on the tower's lower floors, increasing their level on higher floors. A Demon King must always await the heroes at the summit.]

[6. The tower...]

That was...

'The Demon King's Guide.'

The rules I had read until I was sick of them, memorized until my head threatened to burst, and done my utmost to put into practice.

The garbage that had driven me to my death and made me a hero's plaything.

Now I had to read it aloud. I had to swear before everyone that I would faithfully uphold it.

Bullshit.

"Berge Deias?"

Those were idiotic shackles. Utterly misguided garbage, wrong from the very beginning.

I did not want to read it. I had no intention of reading it.

"Please lead us in reciting the great Demon King's Guide without further delay."

The master of ceremonies urged me on.

I knew how grave an offense it was to reject the Guide at an official ceremony in front of everyone.

I also knew it would ruin my brilliant future.

But I had died because of the Guide. I had been toyed with because of it.

"I cannot."

That was why my hatred for it surpassed even the love and blind faith I had once held.

In an instant, the hall fell silent.

"I cannot take that idiotic oath. Following the Demon King's Guide is as foolish and fucking stupid as carrying a dead hatchling into a dragon's lair. That Guide is...!"

Berge shouted, the veins in his neck bulging.

"Garbage!"

"...!"

"...!"

That was the moment the Demon King Military Academy's finest top graduate became its most infamous screwup.