The levitation ship.

As its name suggested, it was a ship, but it could hardly be dismissed as an ordinary vessel.

Levitation stones were a peculiar ore that rose into the sky when infused with mana. The levitation ship was built from those very stones—a treasure of which even the Kingdom of Berft possessed only one.

Imbued with dwarven magical engineering, it was not merely an aerial weapon that could fly through the heavens. It could also cut through the sea and dive beneath it.

Since the tower was underwater, the Empire's demand for the levitation ship had some justification. But the dwarves were extremely reluctant to expose it to outsiders.

Simply possessing a treasure could be poison.

The relatively weak Kingdom of Berft had managed to keep its levitation ship not because the vessel's power overwhelmed other nations, but because there was only one, and no more could be mass-produced.

The nations' mutual determination that if they could not have it, neither could anyone else had created a peculiar balance. Conscious of that balance, Berft used the ship only to defend its own territory, and even then, only in the direst circumstances.

And now they wanted it?

They might call it a loan, but there was no guarantee it would ever be properly returned.

"Absurd."

"The emperor also said this: 'Ultimately, this situation arose because of you dwarves. Therefore, you should be the ones to resolve it. However, you lack the strength to do so, and I will not insist that you clean up your own mess. Instead, should you not provide more substantial support to the coalition striving to resolve it?'"

"Hmm."

He was not wrong.

Whether the forty-nine artisans had been kidnapped and forced into labor, or had all developed dementia and voluntarily helped the Demon King, the fact remained that they had helped him. And as those artisans belonged to the royal workshop, the dwarven kingdom could not be entirely free of responsibility either.

A misunderstanding? Not of their own free will?

Such excuses would carry no weight in the face of so many deaths. Even humans would treat other humans that way. How much worse would it be for them, a different race?

The dwarves recalled the slave hunts humans had once carried out against other races.

"He also said that if we continue to refuse, only the worst possible outcome awaits..."

It was a threat of war. The dwarves stifled groans.

The king changed the subject for a moment.

"... What in the world do you mean, the Tower of Hellfire is underwater?"

"I have only heard it secondhand myself. According to the Empire's findings, the Tower of Hellfire lies in the sea northwest of Dormund."

"A Demon King's tower underwater? That is unprecedented."

But the Demon King of Hellfire had never followed precedent, from beginning to end.

Perhaps it really was possible—if it was the Demon King of Hellfire.

Besides, the emperor had no reason to tell such an outlandish lie.

'Let us look on the bright side. If the Empire tries to keep the levitation ship for itself, the other kingdoms will not sit idly by.'

Akan in particular. Having served as a counterweight to the Empire for hundreds of years, the Kingdom of Akan would not stand by and let it dominate unchecked.

'And we have no choice.'

"... Send another envoy to the Empire."

An agreement was reached: when another raiding party was assembled to attack the Tower of Hellfire, the Kingdom of Berft would provide its levitation ship and one hundred dwarves to operate and maintain it.

* * *

Countless battles broke out in the snowfields.

There were a great many traps, and finding nearly every one across the vast snowfields was all but impossible. The dwarves' traps were that well concealed and elaborate, and the blizzards that were practically synonymous with the snowfields had begun.

The advance slowed. As more snow accumulated, detecting traps became even harder. The vicious cycle repeated.

They blundered into traps every other time, and whenever they did, monsters invariably appeared and attacked from all directions.

Battle, battle, battle, battle.

It was like an antlion's pit. With every step deeper into the snowfields, another obstacle arose to impede them.

Their force of fifty thousand was being whittled away, little by little.

But they had hope.

"Monsters!"

"Follow me!"

Hope named Balaf Dislord.

"Stronger resistance means we are getting closer to the tower. This is the desperate struggle of a Demon King who fears you!"

The hope of knowing exactly where the tower stood.

The coalition was steadily drawing closer to the Tower of Bitter Cold.

"Over three thousand monsters have died."

With every advance, the atmosphere in the Tower of Bitter Cold grew heavier. The more hope the enemy gained, the bleaker things became inside the tower.

"And the traps?"

"All the mana bombs were discovered beforehand. Detection magic is uncovering roughly half the traps that do not use mana."

The situation was different from Berge's fake tower. Back then, he had simply distorted the bombs' mana to make it feel like demonic energy. The tower had been overflowing with demonic energy. Hiding a tree in a forest was easy.

"Of course, we are certainly delaying them, but..."

That did not mean much.

"It is not entirely meaningless," Berge interjected after listening in silence. "Quite a lot of demonic energy points are accumulating as we speak."

The human emotions once focused solely on Berge had spread to all the Demon Kings—especially Reina, who was currently the target of a hero's journey.

Though still not matching Berge, she was gathering large quantities of demonic energy points faster than at any other time since her descent.

As she lifted the dimensional restrictions on herself, those imposed on the demons, demonic creatures, and monsters under her command—on all her servants—would also diminish.

Buying time was not entirely pointless.

But that might matter if this continued for at least several weeks. The coalition would arrive in less than one.

There was simply not enough time.

"..."

Reina fell into thought for a moment. Her somber gaze passed over the demons who trusted and followed her.

Here and there, she saw empty places. Those who had occupied them had crossed a river from which they could never return. For her sake.

Had their deeds on her behalf ever weighed on her as heavily as they did now?

"Berge."

"Speak."

"If I asked to borrow demonic energy points, would you lend them to me?"

"As many as you need."

"If I spent them all on lifting the restrictions, could I win this war?"

"Perhaps."

"Perhaps..."

Reina put a candy in her mouth.

"Everyone, leave. I wish to speak with Berge alone."

"Yes, my lord."

Only the two Demon Kings remained at the top of the tower.

"Perhaps means there is also a chance I would not win, correct?"

"Yes."

"You have changed considerably. Unless I face you directly, I cannot gauge your exact strength."

"And?"

"If even you say that, it must be true."

"I can swear to it if you wish."

Berge thought little of the First Demon Emperor and the Guide, but this time he was sincere.

Balaf Dislord was no ordinary hero. He was not merely some bastard who had killed a single Demon King.

"I am the Demon King responsible for them. I cannot stake all their lives on a 'perhaps' or an 'if.'"

Especially when there was a clear alternative. It would be different if there were none.

"Does that mean...?"

"However."

CRUNCH

Reina bit into the candy. The bright red sweet shattered.

"I will not become the servant of a demon weaker than myself. If you wish to take me as your servant, prove yourself worthy."

"Now?"

"You know better than anyone how little time we have."

"Here?"

"Of course."

"This is your tower. You enjoy its protection, while I am suppressed by it."

"You dared covet me when you cannot overcome even that?"

Reina sneered. The sight overlapped with a scene from the past.

["Berge Deias, arrogant demonic dragon. What you know is not the entirety of the world."]

It had been both advice and mockery, offered when Berge had been running wild. Her tone, as though soothing a small child, had enraged him, and he had told her to shut up and mind her own business.

"... Very well."

Fighting in someone else's tower meant starting at a disadvantage.

Reina Sordein had spent a full century lifting her dimensional restrictions, removing them almost completely. Berge, by contrast, had only had two years. Anyone who knew even a little about Demon Kings would predict Reina's victory.

But Berge was a demonic dragon.

The greatest, strongest race in the Demon Realm.

The restrictions worked proportionally. One percent of a demonic dragon's power was fundamentally different from one percent of another demon's. Their innate abilities were different from the outset.

Moreover, Berge had absorbed Vivian's tower, doubling the efficiency of lifting those restrictions.

By absorbing a Phoenix's corpse and a dragon heart, he had increased his underlying strength itself. One percent of his present power was entirely different from one percent of his former power.

And he was pouring every demonic energy point, accumulating at an unprecedented rate, into lifting the restrictions.

That was why Berge was confident.

No—even if he lacked confidence, he had to have it.

This was an opportunity to take none other than Reina Sordein as his servant. To gain her countless servants as well, swallowing an entire legion whole.

An opportunity to merge another tower with his own and snap Balaf Dislord's neck.

"I will show you why demonic dragons bear that name, and why humans regard me as terror itself."

He spreads his wings.

Horns grow from his head.

Blackish-red scales cover his entire body.

Dragon eyes survey what lies ahead.

"So that is the form of a demonic dragon."

Reina calmly exhales.

A chilling cold merges with the tower, amplifying its power.

CRACKLE

A pure white spear of ice settles into her hand.

"But you, too, must understand."

Demonic dragons are certainly the greatest and strongest of demon races, but...

"Frost demons are also great beings who fall little short of them."

And Reina Sordein is the next leader who will guide those frost demons.

"Come, Berge Deias."

If you want me,

Defeat me.

"Gladly!"

Berge took flight.

Flames surged.

* * *

He could see the ceiling.

Berge shivered in the biting cold. He spat out the blood filling his mouth.

'I lost.'

He had lost.

Even so, Berge smiled.

"I lost. Didn't I?"

"..."

No answer came. Berge lifted his head. Reina's rigid expression was quite a sight.

"You won, but you look like the loser."

"Won? Can this truly be called a victory?"

Reina bit her lip.

"How in the world did this happen? It has only been a little over two years since you descended to Arain."

"Two years for a demonic dragon are not the same as for other demons."

"There is an alien power mingled with your demonic energy. Mana. How did Arain's power blend with yours so well?"

"Become my servant if you want to know."

"Unbelievable."

Reina laughed hollowly.

"Had we fought outside the tower, I would certainly have lost."

Her victory had been by the narrowest margin, even with the tower supporting her. It had suppressed Berge, the intruder, while aiding Reina, its mistress.

That difference had decided the outcome.

But no one present accepted that outcome.

"What, then, were my hundred years worth?"

Reina crunched through her candy in frustration.

Though she had invested heavily in making monsters her servants and building her legion, she had not neglected her personal strength or the lifting of her restrictions.

Demonic dragon or not, he had caught up to a hundred years in a mere two.

"So, will you become my servant?"

"I was the winner."

"A victory you cannot accept yourself is no victory."

"... Balaf Dislord. You said you fought that hero evenly and could not be certain who would win?"

"No. I will win."

"Against a hero empowered by the dimension, making him our natural enemy."

Put another way, that meant...

"I cannot handle him? A single hero who has lived only a few decades?"

"Hmm."

Berge then and Berge now were different.

After he had killed hundreds of heroes and a Star in an explosion, his notoriety had grown exponentially, and the scale of his demonic energy point income had changed as well.

He was continuously pouring all of it into lifting his restrictions. Naturally, the difference was considerable, but he did not bother telling her.

Besides, the hero had not been fighting at full strength either, so he could not be certain...

'I should just keep quiet.'

If she chose to misunderstand in a way that favored him, he could only be grateful.

"If I become your servant, will I learn your method?"

"What method?"

"The method by which you caught up to me in just two years."

A hunger for strength was common to all demons. Even if she valued honor and dignity, her fundamental nature as a demon did not disappear.

"I can tell you the method."

Only the method.

The remains of a Red Dragon, bearing the power of fire, were very likely to be poison to Reina. She would not be able to put it into practice.

"I accept your proposal."

"Really?"

"I do not go back on my word."

"Didn't you say I had to defeat you before you would become my servant?"

"A victory I cannot accept is no victory."

"Those were my words."

"I was thinking the same thing."

"Right. If you say so, then so it is."

Did it matter, when she was volunteering to become his servant?

"... I do not care for that expression."

"You like sweets, don't you? My tower has plenty of chocolate."

"I like candy."

"I will prepare plenty of cherry-flavored candy for you."

"Not bad. But before that."

"Before that?"

"Tell me your plan. Am I simply to become your servant, abandon my tower, and move to yours?"

"There is no need for that."

"Then?"

"I will merge this tower with mine."

"... May I ask you something, if it would not be rude?"

"Go ahead."

"Is there something wrong with your head? Or are you simply insane?"

"That is rude."

'Hmm.'

Why did this feel like déjà vu?