The Regressed Son of a Duke is an Assassin

“Enemies of the Demon King?”

“Yes! We represent a faction that does not follow the Demon King who has lost his past nature and has changed!”

According to the demons I had kept alive for interrogation, they introduced themselves as a group opposing the Demon King, known as his enemies.

When I first heard this, it was a bit absurd.

Not following the changed Demon King?

Does that then mean they follow the Demon King before he changed?

I also asked why they were after me.

Their answer was candid:

“Recently, rumors have spread in our circles that a human has been coming and going from the Demon King’s castle. Amidst that, we got information that a demon, presumed to be human, came here to ‘Arem’. We thought it would be better to target the clueless human rather than the Demon King alone, so we pursued you…”

I couldn’t help but appreciate the frankness of the response.

If they had to choose one of us to extract information from, undoubtedly, they would choose me.

These demons probably knew of the Demon King’s grandeur better than I did.

“And we’re just pawns, so we don’t know much, but…”

Noticing something, one demon continued to speak.

“We’ve heard that other insurgents, not just us, have been in contact with humans.”

“Contact with humans?”

My eyes narrowed sharply.

“Yes! The ‘Demos Faction’—a faction based here in Arem—has been acting on their own recently without sharing information with us. There have been rumors that they might have contacted humans. A demon even claimed to have seen them moving together…”

Rumors are not born without a cause.

There must have been some catalyst, something visible that had started them.

It’s entirely up to me to determine the truth.

An hour after parting ways with the Demon King, I met up with him again, not too far from the spot where we had separated.

“Hey, I don’t mind you moving on your own, but you should at least tell me where we’re supposed to meet. I’ve been stuck here for a whole hour waiting for you!”

If you’re going to lie, at least make it convincing.

Without revealing my thoughts, I threw the demon’s head I had been holding toward him.

The head rolled and stopped at the Demon King’s feet.

“What’s this?”

“Your ‘enemies’ claimed this head. I thought you might know the face…”

“Did you kill them?”

“Self-defense, nothing more.”

The Demon King scrutinized me with a sharp gaze before focusing on the head.

“You must have noticed, right? From the moment we arrived at this residence, there were groups following us.”

My gaze naturally went to his clenched fists.

His knuckles were spattered with smears of blood.

If he has been sitting around for an hour with hands like that, it made no sense.

He must have encountered a similar situation to mine.

“My enemies, you say?”

The Demon King’s eyes returned to me.

“There’s something I should tell you: in this demon world, there might be demons who call me an enemy, but there are no demons that I would call enemies. So…”

He paused slightly before finishing his sentence.

“Don’t just swing your sword around at my kin. I’ll let it slide this time.”

The intense murderous intent I saw at the castle brushed past me like the wind.

So whether they followed him or opposed him, they were all his kin under his dominion?

“I’ll bear that in mind.”

Of course, I couldn’t promise to follow that fully.

The Demon King rose from his place with a wide smile.

“Better this way. Looks like I won’t need to explain. Follow me.”

He then gestured with his eyes toward the door behind him.

-CLANG-

As I flung the door open without restraint, I winced.

A foul stench of fresh blood rushed at me.

It wasn’t an old smell.

An hour or two at most.

Recently spread.

Following him into the room, I saw the bodies of demons sprawled and soaked in blood.

“Just so there’s no misunderstanding—I didn’t do this.”

It would have been evident even without explanation.

The bodies were all cleanly severed as if cut by swords.

They didn’t bear his killing marks.

So, I continued following him into the deepest parts of the space.

The stench of blood was most intense here.

Immediately, I saw a severed body lying atop a table and a head of some unnamed demon rolling beneath.

“The leader of the heads you brought probably is this one. Was his name Demos? One of the leaders of the faction opposing me. I’d been thinking about dealing with him if he crossed a line, but someone has already beaten me to it.”

That was the leader of the faction group the demon had mentioned.

I quickly approached the body to check the severed part first.

A familiar scent unpleasantly struck my nose.

I realized instantly whose handiwork this was.

It bore the mark of a holy sword.

“Do you seem to know who’s responsible?”

“Now I understand why you trust that woman so much.”

I immediately got up and rushed outside.

Looking at the condition of the bodies, the perpetrator wouldn’t have gone far.

They might still be within this residence.

I closed my eyes outside and concentrated.

“Assassination Technique 4: Detecting Killing Intent.”

The sensation was relatively easy to detect, likely due to the distinct atmosphere, compared to the human realm.

I just needed to identify a different energy amidst this unpleasant air.

Like finding a white pebble in a field of black stones.

When I opened my eyes again,

-SWISH!

I darted toward where I felt the energy.

Two to ten.

The energies, which had been stationary, started to move in unison as I did so.

Then, they all moved in one direction as if they had conspired beforehand.

They might as well be demon beasts’ heads for this to make sense.

They were trying to lure me.

I could grab the nearest one for questioning right now, but I chose to see where they were leading me.

Emerging from the residence and continuing the pursuit, a damp, swampy area engulfed in an oppressive atmosphere unfolded before my eyes.

Quiet as it was, demons could have leapt out at any moment.

However, in place of demons, a mysterious group in robes appeared from all directions.

Naturally, they weren’t demons.

In one hand, they held swords; in the other, mana spheres.

Human knights.

More precisely, Frontline Knights.

At last, I had encountered those I needed to find upon arriving in this land.

“…”

As a face emerged from beneath the robe, I locked eyes with the nearest knight watching me.

They looked at me with grave eyes, as if preparing for battle with a beast.

The rest of the knights likely shared the same sentiment.

They were treating me as something more filthy and vile than a mere beast.

-SLICE

Without any disturbance, I quietly drew my blade, Keyram, and aimed it at them.

-CLASH!

The knights, having finished their preparations, struck their formation and charged at me.

“Arise!”

As the mana-infused knights shouted their incantations, the tranquil waters of the swamp suddenly sprang up to engulf me.

It was an attempt to obstruct my vision.

Effortlessly, I swung my sword to split the water.

-SWISH!

Taking advantage of the rift, a sword blade thrust toward me.

I rapidly leaned back, dodging the blade.

Unfazed, the knights leapt into the air and plummeted down with their swords.

-CLANG!

The contact of the clashing blades was sharper than ever before.

Indeed, these were knights seasoned in battle, among the finest.

I might as well have been fighting the most elite knights from the human realm.

Any complacency on my part, and they’d exploit that opening to put me in peril.

I could acknowledge their skill, but…

So what?

Currently, they’re mere puppets, acting without understanding their role, being manipulated at will.

I’ll spare no thoughts for the reputation or achievements these knights have built up to protect the human realm up until today, nor will I feel any guilt for killing them.

With that resolve, I charged in, and at that instant,

-WHOOSH!

A knight suddenly emerged before me with a heavy longsword swinging around.

-CLANG!

His face was obscured by the robe, but the power behind his swing was overwhelmingly strong compared to the others.

Curious about this knight, I examined his sword and discovered something unexpected.

“….!”

An unmistakably familiar seal carved into the blade’s center.

This sword, I know it.

Not vaguely, but unequivocally—I know who its owner is and what it represents.

This was the one and only sword in the human realm meant for a true guardian.

None but one man in the human realm could wield or even possess this blade.

Except for one person.

The Guardian of the Continent.

Only the head of the House of the Duke Berth could possess this sword.

“….”

The sword’s master faced me, calmly meeting my bewildered eyes, and his red eyes shone from within the robe.

* * *

While Syan disappeared somewhere after inspecting the body, Belkaryon remained still for a long time.

He alternated between gazing at the demon corpses and suddenly closing his eyes or sighing, seemingly unable to control his emotions.

“What a pitiful sight, isn’t it?”

“Why are you bringing up this nonsense again?”

As the strange voice echoed in his head, Belkaryon responded with gritted teeth.

“I find this quite pitiable. There’s a limit to rationalization. Aren’t the demons here just as much yours as Besti is?”

“What are you getting at?”

“You’re way past the line already. The scum of the human realm are acting boldly in another’s domain, and how long will you stand by, preaching rationality and just observing? Is this the image of the Demon King you and she had envisioned?”

Belkaryon didn’t answer, merely sealing his lips shut.

“You could be more honest with yourself. Are you afraid of going berserk? You’ve got a friend now to stop you, what’s the problem?”

“Who are you talking about?”

“Naturally, that friend Syan, no?”

Belkaryon’s lips moved erratically, revealing his confusion.

“Who would’ve thought such a being existed among those frail races? Even I am amazed. I almost resent you for not releasing me during the last fight!”

The voice continued to needle the Demon King’s inner nature.

“Don’t hold back any longer, Belkaryon. Let go of your restraints, summon your true form!”

“….”

“Then you’ll see. What form of the Demon King is truly needed for this demon world….”

The voice vanished from his mind with a satisfied chuckle.

-BOOM!

Finally giving in to his emotions, Belkaryon slammed his fist onto the table littered with corpses.

The table split in half with a loud crash.

Belkaryon lifted his head again, trying to control his emotions slowly exhaling.

“Let’s see how far you can go….”