The Boundary Between Man And Demon

I stared at the reddish-black fissure in the sky.

“Now then… how do I go about repairing the barrier?”

I summoned the spell list. As I had hoped, a spell suited to this situation appeared.

Rune Repair: Restores substances composed of magical energy.

“Based on the name, it’s a variation of the ‘Repair’ spell I used on the Demon Castle.”

I raised my right hand toward the sky.

“Rune Repair.”

Following the incantation, the reddish-black crack began to fade and eventually vanished completely.

“Did that seal the hole in the barrier?”

“Detecting now.”

A third eye appeared on Stella’s forehead.

“There are no issues. The damage to the barrier has been completely restored.”

“Good. This should hold for a while. At least for about three months.”

“Three months…?”

“When the hundred Heroes invaded the Demon Realm, a wielder of a specific Miracle Armament broke the barrier. The next time that power can be used is roughly three months from now. Apparently, once ‘Barrier Breaker’ is used, it takes that long to replenish the energy.”

I explained the details to a skeptical Stella.

“Once three months have passed, the Heroes will invade again.”

“…And then, many more demons will be dragged into the fighting.”

“This invasion was merely the beginning. Next time, they plan to open even more holes in the barrier and send in the Hero Army on a massive scale.”

Yes—not just a hundred Heroes, but a thousand, or even ten thousand—Heroes from all over the world. If a force of that size swarmed in, the Demon Realm would truly face extinction.

The reason the war between humans and demons had remained at a stalemate until now was because the demon side had an absolute safe zone: the Demon Realm. Demons could travel freely to the human world, but humans couldn’t even enter the Demon Realm. The war had been a one-sided invasion by the demons.

—Until just the other day.

The human side had devised a way to break the Demon Realm’s barrier and succeeded in sending in the Heroes. The demons, likely never imagining they would be invaded themselves, were caught completely off-guard. That was why the Heroes, myself included, had won victory after victory, dealing massive damage to the demon army. And this time was merely a test case. Next time, a far more powerful force would surely descend.

“We need to organize our defense system by then.”

“Understood. I shall proceed with the maintenance of our depleted troops and armaments on my end.”

“I’m counting on you.”

As I spoke, I let out a small sigh beneath my mask. To think I was revolving my thoughts around intercepting the Heroes who would attack in three months—all from the perspective of the Demon Lord. I felt surprisingly little psychological resistance. Was my heart still that of a human? Or was it already that of a complete demon?

Well, I could worry about that later.

“Let’s go. To the next battlefield.”

There were four more invasion routes used by the Heroes.

“The Eastern region we are heading to next is a very windy place. Please hold on tight so you aren’t thrown off.”

“Ah, right.”

I wrapped my arms around Stella’s waist. …Thinking about it now, this position was a bit embarrassing. Though I wasn’t about to get flustered like a teenager.

“I’m… being held by the Demon Lord…” I heard Stella murmur.

“Hm? Did you say something, Stella?”

“Ah…! M-my apologies! It’s just… this is the first time I’ve ever been so close to a man…”

Stella’s voice was wavering.

“Is that so…?”

“To make such a comment without regard for my station as a subordinate… I am truly sorry.”

“No, you don’t have to be so formal. Even if you’re a subordinate, I feel more like you’re my partner.”

Partner—.

The moment I said that word, a sharp pain throbbed in my chest. I remembered Lyle—my former partner and beloved disciple.

“Such words are more than I deserve, my Demon Lord,” Stella’s voice trembled. “For someone like me.”

“See, you’re being formal again.”

I gave a wry smile. Just exchanging words with Stella made the pain in my chest fade. It felt like I was being healed.

“Alright. For starters, call me Fried.”

“Eh? E-eh…!?”

I had suggested it casually to break through Stella’s stiffness, but she was strangely agitated.

“Ah, I guess it wouldn’t look right in front of everyone else. How about just when it’s the two of us?”

“…I am to call you… by your name?”

“If you’re okay with it, Stella.”

“Th-then…”

Stella turned back and looked at me.

“Fried…-sama…”

For some reason, her face was flushed.

The Eastern region was a grassland area. However, it wasn’t a pastoral landscape like the human world. Strange, twisted plants grew everywhere, giving off an incredibly eerie vibe.

Standing dozens of meters ahead was a massive man. Surrounding him were countless corpses. A mountain of dead demons.

“That guy is—”

I stiffened beneath my mask.

“Fried-sama?”

“Stay back, Stella.”

I took a step forward. The wind made the hem of my robe flutter.

“I know him.”

I had only seen his face once or twice, but his fame was well-known to me.

“The Hero Claudio—also known as ‘Bloody Claudio.’ His demon kill count is in the top five of all history.”

A battle-hardened veteran.

“Hmph, that crest… a Demon Lord? Your appearance is a bit different from what I heard, though.”

Claudio looked at me and curled his lip into a grin. His gaze was fixed on my hand. More accurately, on the Demon Lord’s crest on the back of my hand.

“I was beginning to think these lot weren’t a sufficient challenge.”

Claudio laughed, baring his fang-like canines. He crushed a skull beneath his feet.

“You—”

At his act of desecrating the dead, I clenched my fist.

“Demon Lord, you look like you might actually be able to serve as a proper opponent. I demand a duel as a warrior.”

“…If you are a warrior, have you no respect for those you fight?”

“Respect? For demons? Don’t make me laugh.”

“Demon… Lord…-sama… gah.”

Claudio plunged his sword into a nearby demon—one who was still barely breathing. After a few twitches, the demon stopped moving.

“There is no need to show respect to vermin.”

“You…!”

I gritted my teeth.

“That one was mortally wounded anyway. I simply put him out of his misery, you see?”

“You were just mocking him.”

“Does a great Demon Lord actually mourn the death of a subordinate? Hmph. I, too, have lost many comrades.”

Claudio raised an oversized greatsword into a mid-level guard.

“To reach this point, all the other Heroes died.”

A low humming sound, like the buzzing of a fly, vibrated through the air.

“Miracle Armament: Arondight, huh.”

I had heard of Claudio’s Miracle Armament; it caused the blade to vibrate at high speeds, capable of slicing through anything it touched.

“I planned to wipe out these soldiers and then march on your castle—but this saves me the trouble. Now, let us settle this fairly!”

Claudio raised his greatsword and charged.

“Ooooooooooooooooh!”

With a thunderous roar, Arondight was swung down.

“Dark Breaker.”

Along with the incantation, a black radiance formed in front of me. Becoming a blade of light, it shot forward and intercepted Arondight.

Snap.

With a high-pitched sound, Arondight snapped clean in half.

“I-impossible… a Miracle Armament… broken!?”

Claudio looked aghast. The spell I had just cast, ‘Dark Breaker,’ was a spell specifically for destroying weapons. It was my first time trying it, but it seemed quite practical.

“You monster…!”

“There’s no need to show respect to vermin, was it?”

I held my hand out in front of his face.

“In that case, I too… shall show you no respect. I will simply erase you.”

I felt my heart being painted over in jet black. It felt as though something was sedimenting in the depths of my chest.

“W-wait…”

Claudio’s face twisted in terror.

“Help… me…”

The voice pleading was raspy; there was no longer any trace of the battle-hardened veteran.

“How many people did you kill who begged for their lives just like that?”

With those words, I fired a magic bullet. Engulfed in a black flash, Claudio vanished before he even had time to scream.

After repairing the barrier here as well, I headed to the next front with Stella. There were a few Heroes there too, but they were no match for me. I swept them away and sealed the hole in the barrier. Then, I drove off the Heroes and repaired the holes in the remaining two locations.

Thus, all five holes in the barrier were sealed. For now, it served as an adequate emergency measure. The brief defense of the Demon Realm had ended, and Stella and I returned to the Demon Castle.

There was nothing but darkness spreading out.

“Where is the exit—”

He continued walking, feeling completely lost. He was a boy with blonde hair, blue eyes, and refined, beautiful features. His memories were still muddled.

Who was he? Why was he here? His head was foggy, and he couldn’t remember.

“Right, I… my Master…”

Suddenly, a fragment of memory returned.

“No, I killed Fried, and then…”

Along with memories that were becoming clearer bit by bit, he—the Hero Lyle—pressed forward.