"How did you really do it?"

After the Harmony of Towers ended, Berge arrived at the Tower of Bitter Cold. Reina had asked to speak with him briefly.

Her question was more or less what he had expected.

No Demon King was naive enough to take Berge at his word when he said the heroes had foolishly searched the wrong place. Yet they had refrained from challenging him further.

'That bastard Ugar let it go because Jason did...'

As for Reina, she was his ally and had not wanted to put him at a disadvantage in front of everyone.

'What should I do?'

It was not that she expected nothing in return, but from beginning to end, she had genuinely helped Berge. As her ally, he ought to repay her. A relationship where one side only gave and the other only received could hardly be called an alliance.

But he could not admit that he had abducted the dwarven princess and craftsmen and used them to attach legs to his tower. Not only was it valuable information that would cause an enormous stir, he had sworn before everyone that he had never abducted the dwarves.

For Reina, who valued honor and good faith, that would be reason enough for an ally to become a sworn enemy in an instant.

So Berge decided to mix a little truth with lies. It could also serve as a small repayment for everything she had given him so far.

"I have never heard of a tower disappearing."

"The tower remained exactly where it was."

"Then?"

"But it concealed itself for a while."

"You hid the tower?"

"Concealment magic. I cast it over the entire tower, hiding it completely when they arrived."

"... Is that possible?"

As far as Reina knew, towers had no such power.

"Can you claim to know everything about a tower's powers?"

"... No, but..."

The Demon King Military Academy did teach its students about towers. And after becoming Demon Kings, descending, and building their towers, they experimented with them in various ways.

But most of those experiments were confined to the interior: altering the structure, strengthening floors, and summoning demonic creatures. They were Demon Kings, after all. That much was enough—in other dimensions.

That complacency had persisted for thousands of years and was now passed down almost as established doctrine. No one bothered to learn more about a tower's powers.

The Demon King Military Academy had stagnated to the point of rotting.

He had not understood that before, but he did now.

"Are you saying one of a tower's powers allows it to hide itself?"

"No. It has no such power."

"Then?"

"But it does have the ability to integrate artifacts into itself."

"Integrate artifacts?"

"What kind doesn't matter. As long as it has a magical function, the tower can recognize it. You can spend demonic energy points to enhance that function and integrate it into the tower. The function then extends throughout the entire tower."

"... That's possible?"

"I have no reason to lie to you."

"Even so, are you saying that alone kept the expedition from detecting it?"

Reina was not easily convinced. Naturally so. This expedition had been stronger than any other: Balaf Dislord, Gillian Aint, Aina Diaphrin, and even Watton Collo.

Stars were those who stood out even among heroes, and their exceptional abilities included detecting demonic energy. The stronger a hero's power—their interference—the greater their revulsion and hostility toward the demonic energy that opposed it.

She could not believe that integrating a single artifact into a tower had let it evade all of them.

And indeed, it could not have concealed the tower. Had Berge merely hidden it and trusted the Mana Ghost, he would not be here now.

"It's possible. It simply takes a corresponding amount of demonic energy points to fool them."

"Ah."

Reina nodded.

Demonic energy points made it understandable. If he had used a truly enormous amount of them to borrow some of the tower's power, he could fool even Balaf Dislord.

If he could not, it only meant he lacked sufficient demonic energy.

"Then you must be..."

"That's right. Luckily, they withdrew this time, but there's no telling what will happen next. Still, now that rumors say the tower is gone, I think I'm safe for a while."

"Was that why you abducted those princesses over the past few months?"

"Yes. To obtain as many demonic energy points as possible. I'd die anyway if I couldn't evade the Empire's hero's journey, so I had no time to weigh every little consideration."

"Integrating artifacts..."

Reina stroked the ring on her finger.

"This artifact contains defensive magic, but I assume you don't mean rings like this?"

"Correct. Rather than a simple artifact, it would be more accurate to call it an installed magical engineering device."

"I understand. You mean something like the Breizna installed at the academy?"

The Breizna was an artifact created by a demon named Breizna. It was a training device that made the surrounding mana heavy, making training harder for Demon Kings.

"That's right."

"It will be worth looking into."

Reina nodded.

"Thank you. I learned something important quite unexpectedly."

"It's a small token of thanks for what you've done for me."

"A very small one, considering."

"... Of course, I didn't say that was everything. I'm still alive, so I'll have opportunities to repay you in time."

"I'm joking. Focus on surviving first. The Empire won't stop here."

"Of course."

"I'll have to contact the Demon Realm and bring over my family's artifacts."

"That's a good idea."

It seemed the snowfields were about to grow even colder.

* * *

The shock of the Tower of Hellfire's disappearance struck the entire continent, but nowhere felt its repercussions more than the Empire. And no one had more complicated feelings about it than the Third Prince, Martin Jespine.

All the more so because, no sooner had news of the imperial hero's journey's failure spread, than he received a call from the very person who had made the Empire eat shit.

"... You're coming to the Empire?"

『Yes.』

"Do you have any idea how much turmoil you've caused here?"

『Must I take even that into consideration?』

"How on earth did you hide the tower?"

『I didn't hide it. Those fools simply failed to find it.』

"You expect me to believe that?"

『And if you don't?』

As the Demon King's gaze turned icy, Martin swallowed his anger. He must not forget: it was the Demon King who held the upper hand now.

With Kaede captive and the key to the treasure vault handed over, he might as well have been on a leash.

"... No. I spoke out of turn. I apologize."

『As a Demon King, I shall show mercy. In any case, I'll be there soon, so make the preparations. See that I can enter the secret vault immediately.』

"What do you mean? What preparations?"

『What are you talking about? Weren't you the one who said I could enter the secret vault as your escort knight?』

"..."

Martin unconsciously stifled a groan. Come to think of it, he had said that.

But he had never imagined the Demon King would seek official entry into the secret vault through him. Having taken the token and Martin's blood, to which it responded, he had assumed the Demon King would sneak in.

『Don't tell me...』

"O-of course I remember. But aren't you a Demon King? If a Demon King comes to the imperial capital..."

『That isn't your concern. But I can assure you that my demonic energy, at least, won't cause you trouble.』

Martin bit his lip.

"What will you do about the tower? They failed once, but this isn't the end."

The atmosphere was ominous. The emperor was furious, and Balaf Dislord, who had led the expedition, was outraged. Balaf had never known failure before. His first defeat had shocked the public, and he himself could not readily accept it.

A second hero's journey was being planned with the emperor's wholehearted support.

No, in truth, there was hardly anything to prepare. The hero's journey had failed, but only because they had not found the tower. They had suffered almost no losses.

They only needed to set out again as they were, so it would not take long. And this time, they would not simply withdraw as before just because the tower was not in its original location.

『It wouldn't matter if they tried a hundred times.』

"... Remarkable confidence."

That confidence put Martin in a terribly difficult position. But having already assured the Demon King he could do it, he could not simply refuse. Nor could he expect a rational response from a Demon King.

"... Very well."

『I'll see you soon.』

The connection ended.

"... What should I do?"

There was no clear solution.

He did not know that the Demon King, sensing something odd in his attitude, had sought out his younger sister.

* * *

"Apparently, a second hero's journey will begin soon."

"I thought it might. In fact, with a force that large, they could search all of Erjest without much difficulty. You'll have to move the tower again, then."

When a Demon King was absent, some of the tower's main powers were restricted. An adjutant could not fully replace a Demon King.

If the expedition arrived while he was in the Empire, it would be over.

"I will."

"Where do you have in mind?"

"North. Somewhere the humans will never find it."

Moving the tower required an enormous amount of demonic energy. Yet Berge was confident because he had more than enough.

[12,025,914pt]

In just one week, his depleted demonic energy had grown far beyond its previous level. It was not difficult to guess why.

Because a hero's journey composed entirely of heroes had failed. Because Balaf Dislord had led that expedition, and it had included four Stars. Because the Demon King who had killed even Dafner Philiain and abducted five princesses had once again vanished without a trace.

All of it had intertwined to create terror.

That fear had given Berge an enormous amount of demonic energy, and continued to do so.

"I don't think that's a particularly good idea."

"Not a good idea?"

"As long as we remain within Erjest, they will eventually find the tower. Surely we can't keep moving forever?"

"True."

"Then why not leave Erjest altogether?"

"You know that's impossible."

To the south lay the human kingdoms. There was no hiding an enormous tower that moved with thunderous, pounding steps.

The eastern snowfields were ideal, untouched by human hands—but Reina Sordein's influence reached deep into them.

"It isn't necessarily impossible. I've never heard that a Demon King's tower isn't waterproof."

"...!"

Berge's eyes widened.

"So what you're saying is..."

"Probably exactly what you're thinking. I've already asked the dwarves, too. They said a little seawater wouldn't make it rust or break down."

The sea was vast. And it belonged to no one.

Even if humans claimed territorial waters, they could not plant their flags deep beneath the sea.

"You...!"

Berge clasped both of Gordon's hands.

"You're a genius! No wonder you were the top graduate of the Demon Training Academy!"

"Thank you. But how could I compare to you, my lord, the top graduate of the Demon King Military Academy?"

"When I first descended, I wondered how on earth I was supposed to teach this idiot..."

"I wasn't quite that bad."

"You weren't?"

"... I simply didn't know the circumstances of this dimension, Arain. Yes, that's exactly it. I didn't know. I didn't know it was this shitty."

"Well, it doesn't matter. I can already picture the humans' bewildered faces when they search all of Mount Erjest and still fail to find the tower."

"All the more so when you consider the losses they'll suffer to monsters while poking around everywhere."

"You're an excellent adjutant."

"And you are the finest Demon King, my lord."

The Demon King and the dark elf looked at each other and smiled deviously.