Somehow, I had found myself in Darkland during the summer vacation, and now, during the winter break, I was once again headed there.

Of course, this time, my companion was not Ellen, the next Hero, but the Princess and the greatest swordsman of the continent.

The place Ellen and I had ventured to was merely the outskirts of Darkland.

The Demon King's castle, our current destination, was situated deep within Darkland. The allied forces had advanced in a single-point breakthrough formation, successfully capturing the castle. However, there had been no exploration of the surrounding areas.

Although the adventurers had been leading the Darkland pioneering project, they had yet to search a vast area.

Our party consisted of only three people: myself, Saviolin Turner, and Charlotte. There was no need for additional escorts or attendants, as deploying a large force would only cause unnecessary commotion.

"We'll have to pass through quite a few warp gates, Your Highness."

"Yes."

The allied forces had built warp gates at regular intervals during their advance to secure supplies. Naturally, during the war, these warp gates would have been prime targets for the Demon King's army.

We planned to travel through the large warp gates to reach the Egsian forward base, then follow the allied forces' route directly to the Demon King's castle.

While it would take some time to activate the dormant gates, there wasn't much actual travel time involved, as a warp gate had been installed right in front of the castle after the war.

Charlotte wore a tense expression.

To her, the Demon King's castle must have seemed like hell itself.

She was returning to a place she never wanted to see again, only because there might be a slim chance of finding a clue to resolve her situation.

Undoubtedly, Charlotte's emotions were complicated at that moment, and I shared her feelings.

------

At present, the Demon King's castle was occupied by the Empire's forces. While they had thoroughly plundered the castle, the search and investigation of the entire place had not yet been completed.

Our party had quickly traveled through the warp gates, passing the Egsian forward base, and had managed to arrive at the Demon King's castle at an astonishing speed.

"..."

"..."

Both Charlotte and I were speechless as we looked upon the desolate sight of the castle.

The massive gray fortress stood beneath the clear blue winter sky.

The aftermath of the raging war could still be seen all around the Demon King's castle.

Traces of powerful magic and siege weaponry marked the castle walls.

"So this is... the Demon King's castle."

Saviolin Turner, who had not participated in the great war against the demons, was seeing the castle for the first time. I could not tell what emotions she felt as she looked upon the remnants of humanity's great victory.

Regardless of whether Bertus would find out, we had no intention of advertising our arrival. If influential figures appeared at the garrison, it would undoubtedly cause an annoying commotion.

Hence, upon arriving at the castle, the three of us donned our robes to conceal our identities.

"Your Highness, I am Count Alfred, currently serving as the commander-in-chief of the Demon King's Castle garrison."

It seemed that only the commander, who had been informed of our arrival in advance, had come out to greet us alone, so as not to cause any unnecessary commotion. Charlotte and Saviolin Turner's concerns were palpable.

"Ah, I see. It's nice to meet you, Count Alfred."

Bertus would likely be aware that Charlotte's power is related to the Demon King; she simply chooses not to use it as a weapon.

Thus, Charlotte's visit to the Demon King's Castle garrison is under the pretense of an inspection. She whispered this explanation to me.

Although not always active, the presence of a warp gate here ensured that the garrison's supplies were in excellent condition. Instead of tents, proper buildings had been constructed around the Demon King's Castle, and the soldiers seemed more focused on reconnaissance and research than on combat.

Under the guidance of Commander Alfred, we headed towards the garrison's command center.

Our visit wasn't entirely top secret, but it wasn't public either. Only a select few, including the commander, knew we were coming today.

Count Alfred appeared to view me as a mere attendant.

After a brief meal with the commander, he escorted us to the command center's map room.

Charlotte's ostensible purpose was to check on the investigation of the Demon King's Castle.

In the middle of the map room was a table with a model of the castle's architecture, and the walls were covered in drawings that appeared to be targeting the Demon King's Castle.

"The Demon King's Castle is incredibly vast, as it was once the abode of the Demon King. Thus, our exploration is not yet complete."

"Is it that extensive?"

"Yes."

The architectural model included a detailed representation of the collapsed castle walls.

In reality, the Demon King's Castle was immense in scale.

Just as the Imperial Palace of Emperatos was enormous, so too was the Demon King's Castle.

While the Imperial Palace had one palace in each cardinal direction, the Demon King's Castle featured a massive central palace surrounded by countless auxiliary buildings of considerable size.

"There are still areas where traps are active, so we're proceeding with caution to prevent casualties until we have a thorough understanding..."

Charlotte's words seemed to be a criticism of their progress, and the commander mumbled uncomfortably.

"I think it's right to proceed cautiously since there's no rush. I didn't mean to criticize, Commander."

"Thank you, Your Highness."

The Demon King's Castle was so vast that the investigation was not yet complete.

The reason being that there were still areas with active traps.

Although there was a model of the castle's exterior, there were still unexplored areas on the targeting map.

Nevertheless, the commander began to explain, pointing at the targeting map and the three-dimensional model.

The auxiliary building, as large as a palace, was a barracks.

It was quite odd for me, the prince of the Demon Realm, to learn something new from a garrison commander.

"It is presumed that a standing army was stationed in the barracks. However, no matter how large it may be, it couldn't possibly accommodate all the numerous demons and monsters that fought against us during the Great Demon War. Hence, we assume that they must have conscripted demons residing in other regions."

"Indeed."

At the time of the Great Demon War, the Demon King's castle housed a military force far exceeding its capacity.

The commander added that there wouldn't have been so many soldiers in the castle during peacetime.

"On the first floor of the Demon King's Palace, there are facilities for living, including a dining hall and a banquet hall. And in the center of the palace, do you see this courtyard?"

"Yes."

The center of the Demon King's Palace was wide open, with a vast, open space.

There were destroyed pillars and statues.

Every piece of shattered debris was intricately depicted.

Even though it was just a model, one could sense that an extraordinary battle had taken place here on a massive scale.

"Could this be...?"

Charlotte looked at the commander, who nodded.

"Yes."

The enormous courtyard of the Demon King's Palace.

"This is where Ragan Artorius fought against the Demon King."

In the heart of the Demon Realm, the decisive battle between the hero and the Demon King had taken place.

Although we hadn't witnessed the battle, Charlotte and I had heard the earth-shattering noise.

Charlotte shivered slightly, and I silently swallowed.

The remnants of the Demon King.

Vaguely, Charlotte thought that if she could touch them, she might gain some knowledge or resolve her current situation.

"I need to visit this place."

So, it was only natural for Charlotte to say that.

------

The Demon King's castle was so vast that we each rode horses to get around.

I had learned horseback riding at the temple, so I was able to ride without any issues.

Since the castle was an investigation area, there were no people living inside unless they had a special mission.

Thus, there was a large village surrounding the castle, called the garrison.

It was unclear whether there had originally been a village for demons like the Demon King's castle nearby. If there hadn't been one, it never existed, but if there had been one, all traces of it would have vanished due to the war.

"Which areas are confirmed to be safe so far?"

At Charlotte's question, the commander answered.

"All the auxiliary buildings have been secured, and we have confirmed that there are no functioning traps on the ground level of the Demon King's castle. However, the underground is still dangerous, so please refrain from venturing there. As long as you don't go too deep underground, there shouldn't be any major issues."

This meant there was nothing to discover on the ground level of the Demon King's castle.

Would I have to go underground to learn whatever I needed to know? Charlotte, riding alongside the commander, asked another question.

"Have many soldiers fallen victim to traps?"

"Not just soldiers. Experienced rangers, knights, and even mages often fall prey as well. It's fortunate if they only end up injured, but some victims of mental traps have their minds broken. That's why we're particularly cautious when exploring underground areas."

"Hmm... I see."

These were not traps in some remote dungeon, but in the Demon King's castle itself.

Charlotte couldn't help but gulp at the thought of dying or becoming permanently disabled by carelessly triggering one.

Even without considering Bertus's problem, the Demon King's castle wasn't a particularly safe place.

The commander had repeatedly warned that the underground areas were not properly secured and should be avoided.

But Charlotte, like me and Saviolin Turner, probably thought the same. If there were any clues, they would be in the underground area.

Soon, we arrived at the entrance to the grand and majestic Demon King's palace.

The girl who was thought to be a pitiable hostage kidnapped by the Demon King was, in fact, a princess. And she had immediately sensed the impending doom of her own death upon being rescued.

She had returned with Dyrus, acquired a teleport scroll, and galloped with all her might to escape the clutches of the knights of the Salerian duchy.

Without me, Charlotte would have died.

I wonder what Charlotte is thinking now.

Is she thinking about the terror, pain, and terrible times she endured?

"..."

But the fleeting expression on Charlotte's face seemed full of sadness. It didn't seem like she was thinking about her anger and pain.

I know what she's thinking without having to ask.

She's thinking about Valier.

He had saved her but suddenly disappeared, and after briefly corresponding through letters, he had cut off contact himself.

Now she could only ponder his true identity amidst her anguish.

And here I am, by Charlotte's side as Reinhardt.

"Let's go in."

Charlotte, who had dismounted from her horse, spoke bravely.

------

The path leading to the inner courtyard of the Demon King's palace wasn't particularly complicated. It was just that the palace was so massive that we had to pass through long and wide corridors and several halls.

Signs of battle still remained within the castle.

"Of course... Your Highness knows this better than anyone... After the Demon King's death, all the demonkind surrendered."

"I see."

As we walked, the commander pointed out the signs of battle in the grand halls within the palace.

"So the traces inside the palace mostly belong to the hero's party."

"Ah, I see."

The Demon King's castle had not been breached until his death.

And after the surrender, all battles had ceased, so there had been no fighting between the Demon King's army and the allied forces within the palace.

The broken furniture and statues, collapsed walls, and other traces were the results of the Demon King's forces and the hero's party clashing within the palace.

The commander explained various things as we walked through the palace.

His tone carried a sense of pride.

The great victory of humanity.

And the Demon King's castle was much like a museum commemorating that victory.

It seemed so, and that statement was not too far from the truth.

Standing in front of the collapsed wall of a massive hall that probably once served as a dining area, the commander spoke. He demonstrated a moment of silence right there.

A single white flower lay where he had paid his respects.

"Here, the body of Ragdina Olfi was found."

The place where the remains of one of the hero's party members were discovered.

After the Demon King's death, they would have recovered all the corpses, so the bodies of the hero's party members would have been found scattered throughout the castle.

The locations where they had been found would have been recorded as well.

"And over there, the body of Archirion, one of the Four Heavenly Kings, was found along with hers."

Ragdina Olfi.

The one who had taken on the ranger position in the party.

I had never heard of Archirion, as I had not set up the Four Heavenly Kings myself.

What I had set up was the fact that as the hero party defeated each of the Four Heavenly Kings, one of them died in the process.

And in the end, only Ragan Artorius remained to face the Demon King.

Having them die one by one as they defeated each of the Four Heavenly Kings was a cliché in its own right, but I had never really given it any thought.

Perhaps there was a background to the Four Heavenly Kings each taking on the hero party one by one.

It was impossible to know now.

Saviolin Turner and Charlotte followed the commander, silently bowing their heads in tribute at the spot, as did I.

It couldn't exactly be called a tour, but the commander led us around as if it were his duty.

This time, it was not a hall but a massive corridor. There, too, a white flower that seemed recently placed lay.

It appeared that someone brought flowers here every day.

The pillars of the corridor had collapsed, and somewhere among the fallen pillars, the commander paid his respects once more.

"Here, the body of Mullerun, the mage of the hero party, was found."

"With the body of one of the Four Heavenly Kings, Succubus Queen Reina."

Succubus Queen Reina.

Airi's mother.

It was a name I had heard before, so it carried a weight that was far from insignificant.

The commander spoke quietly while staring at the traces of the collapse.

"Succubus Queen Reina was a very serious problem. On nights when she exerted her influence, tens of thousands of soldiers were too afraid to fall asleep due to her nightmare powers, and those who couldn't resist sleep often never woke up again."

He emphasized several times that the true terror of the Succubus Queen lay in the fact that her power was nightmares.

Although her power might not have been able to enter the minds of those with strong mental resistance or anti-magic training, countless soldiers without such resistance became unwitting victims of her nightmares.

"In fact, excluding Larken Simonstite, the Succubus Queen and her kind probably killed the most coalition soldiers."

Upon hearing the name Larken Simonstite, Saviolin Turner seemed to flinch slightly.

The commander spoke and walked ahead once more.

"Based on the circumstances, I believe the problem might have been the excessive amplification of magical power to save our companions from the powerful enchantment of the Succubus Queen..."

Commander Alfred visited the locations where the bodies of the hero's companions had been discovered, one by one.

Their original goal was to visit the place where Ragan Artorius and Demon King Valier had fought, but Charlotte had no particular comment on this.

Since the heroes had saved her life, she felt it was her duty to confirm the details.

After passing the place where the priest Sheridan had died, the commander sighed heavily when they reached the spot where the demon swordsman Seizaridia, presumed to be one of the last two standing alongside Ragan Artorius, had perished.

"Here, the bodies of the greatest demon, Larken Simonstite, and demon swordsman Seizaridia were found. It is presumed that the battle between Ragan Artorius and the Demon King took place immediately after."

Larken Simonstite.

I heard that both Airi and I had learned swordsmanship from him. I was a slacker, while Airi was an honor student.

Of course, I don't know much about him.

"......"

However, Saviolin Turner stared solemnly at the scene where an intense battle had undoubtedly taken place, her expression hardened.

"I wanted to kill that man with my own hands."

Saviolin Turner's fingers trembled slightly.

Neither Charlotte nor the commander said anything, as if they already knew.

It was obvious that I was the only one who didn't know why Saviolin Turner was saying such things.

Sensing my confusion, she looked at me and offered a bittersweet smile.

"He was my teacher."

"…What?!"

I couldn't help but be startled by the completely unexpected revelation. Charlotte and the commander stared at me, taken aback by my astonishment.

"You mean… you learned swordsmanship from a demon?"

"…?"

"Hmm?"

Saviolin Turner mumbled, folding her arms.

"It seems you didn't know. Well, it's possible you wouldn't… Larken Simonstite was human."

He was a human, ranked among the top four demon generals?

Wait, isn't it a big deal not knowing this? Fortunately, my humble background allowed me to let it pass.

My jaw dropped.

"A traitor of the empire who deserved to be torn apart."

A quiet rage burned in Saviolin Turner's eyes.

Come to think of it.

'Yes, the prince and princess learned swordsmanship from the first demon general, Sir Larken Simonstite.'

The title 'Sir.'

Upon reflection, it suited a knight, didn't it?