Vol 1 Chapter 15: The Path to My Wish (Great Labyrinth Arc)

With Yuu leading the way, we could reach the place where Nio was sealed in just a few hours.

However, along the way, Yuu sensed the presence of numerous monsters. She also detected multiple high-ranking demons stationed as guards, seemingly to protect Nio’s seal.

But that didn’t matter. I had come this far, and I had a powerful ally by my side.

And I still had my trump card—the high-risk, high-reward power of Asterion.

That meant a direct assault was the best approach. Trying to sneak in would be pointless—Yuu’s mana would be detected either way, and the Demon King was already desperately searching for us.

Before they could fully prepare their defenses, we would storm in while their forces were still scattered searching for us, rescue Nio, and then take down the Demon King before escaping the labyrinth.

With Yuu, an Ancient Elf from that era, Nio, who also knew the truth, and me, the Sword Saint—once we took the Demon King’s head and exposed the truth, Sieg and the King would be left to the judgment of the people.

So, for now, no need to overcomplicate things. The only question that mattered was: where were the Demon King and Sieg?

The Demon King, as the ruler of the Great Labyrinth of Grimoire, was likely still here. But Sieg was another story.

His obsession with me was purely because he wanted to claim Asterion. A little humiliation wouldn’t be enough to keep him lurking around.

That said, there was still a chance he was waiting with the Demon King.

With that in mind, as Yuu and I cut our way through the monsters in the labyrinth, I drove my sword into a humanoid demon, glaring down at it as I asked,

“You can talk, can’t you? So I’ll ask once—where are the Demon King and the Hero?”

With its leg tendon slashed, the demon couldn’t even stand. As I pressed Asterion to its throat, the high-ranking demon stammered, its expression twisted in terror.

“I-I don’t know!”

“The Demon King has hidden himself! And the Hero?! Like we’d know anyth—”

“Got it.”

No need to hear the rest. I finished the job, slicing it down.

The other monsters, now soaked in its blood, froze in fear. Not that I cared.

I raised Asterion and fixed my gaze on them.

“What’s wrong? If you want to die, step right up. I’m in a hurry… for a lot of reasons.”

Rescuing Nio, who I’d spent two years searching for. Taking revenge on Sieg for his betrayal. And facing off against the Demon King, the one behind it all.

To put an end to everything, it was time to unleash the brute force I had been holding back.

“If you won’t come to me—then I’ll come to you!”

With that, I charged into the screaming horde, relentlessly swinging Asterion.

High-ranking demons, hordes of lesser monsters—it didn’t matter.

Ten years of training the basics. Two years of pushing myself to the brink of death in real battles.

There wasn’t a single one of them who could best me. None even managed to land a hit.

I pushed Asterion’s physical enhancement to its limit, adjusting my enchantments on the fly to match the situation. Yuu, meanwhile, took care of enemies beyond my reach with her magic.

“A-Are you seeing this?! That woman’s spamming top-tier magic without even chanting!”

“And she’s using different elements! How the hell do we block that?!”

“We can’t! There’s no way we can beat those freaks!”

Their desperate wails filled the battlefield—shortly before they were all silenced.

I shook my head, sending droplets of blood flying. Judging by the splatter, it must have been mostly monster blood. I had charged in, hacking away with Asterion, and was now completely drenched in it.

Seeing me like this, even Yuu, ever composed, tensed up slightly. She silently cast a water spell to wash the blood off me.

“Y-you’re incredibly strong… or rather, I should say, completely ruthless… It’s a little terrifying. No, extremely terrifying…”

“You already saw a glimpse of it earlier, right? I had to hold back against that armored bastard since I was protecting you, but now that I can move freely, there’s no issue.”

“No issue?! At this rate, you don’t even need my support… Ah, but this kind of overwhelming strength is… really attractive, too. It feels like I could entrust everything to you… Coming from someone who spent most of her past fighting, that’s very appealing…”

At first, she looked like she was grimacing in fear, but before I knew it, she had slipped into a dazed trance.

…Well, with this much power, I should be able to handle the Demon King.

But if Sieg or some unexpected foe was waiting, things could get complicated.

For two years, I fought battles no one else could keep up with. But now, I had Yuu—a partner who could fight alongside me.

I’d stay at the front, and Yuu would cover the rear. This formation worked.

“Just to confirm—do you still have enough mana left? I’ve got another trump card up my sleeve, but considering our opponent, I need to know exactly what you can do.”

“Hmm… If it’s just this level of combat, I could keep going for a full day without breaking a sweat.”

“I’m not great with magic, but… is that even possible?”

Yuu already knew about my situation with Asterion preventing me from casting even the weakest spells. Smiling confidently, she explained,

“I’ve already fired dozens of what would have been considered high-tier spells in my time. Judging from how the monsters reacted, either the magical system has changed, or its standards have dropped—since they treated those spells as top-tier magic. And if that’s enough to wipe them out, then I can handle however many of these weaklings you throw at me.

And if a true powerhouse does show up, I’ll simply use a myth-class spell to deal with them.”

“Myth-class? The hell is that?”

“I suppose it has been lost to time… Simply put, it’s magic so powerful and devastating that the gods themselves feared it, likening its effects to divine wrath. Even I can only cast one or two in a day. It also takes considerable time to activate, but nothing survives it once it lands.”

“When you ask about the Demon King too?” I inquired, and Yuu nodded. However, she explained that against the Demon King, unleashing that kind of magic was nearly impossible—and even if it were cast, landing it was out of the question.

“To think such magnificent magic exists. With my makeshift knowledge, I doubt I could ever begin to grasp the true essence of magic,” I remarked.

At my words, Yuu paused to think for a moment, then tilted her head and asked,
“Um, not only the myth-class magic but also the no-chant spells and rapid-fire, multi-element magic are pretty amazing—but Kaim, aren’t you surprised?”

“Unfortunately, I’ve never had much to do with magic before getting Asterion. I’ve never used it or practiced it, so I can’t really tell just how incredible it is,” I replied.

I added that my understanding is basically limited to a rough, makeshift grasp—and then we pressed onward. Even if I don’t fully understand all the intricacies, if that level of power is gathering, maybe I won’t even have to use my trump card.

“Let’s hurry—rescue Nio, take down the Demon King, and finish this once and for all!” I declared.

“Yes!” Yuu responded brightly.

　####

Taking her answer to heart, we rushed toward the place where Nio awaited.

After several battles, we emerged into a vast chamber enclosed by an iron wall—a secluded area where Yuu had once been sealed. The room boasted a ceiling that made you look up and an open layout resembling a great plain. At the far end, there was a door. Squinting, Yuu said,
“Beyond that lies another open area. Nio should be there.”

Even when she mentioned Nio’s name, Yuu didn’t hide any emotion—her voice was unusually cold. It seemed there was something between them after all. But true to her promise, she wasn’t lying.

That aside, something was off.

“There’s no sign of the Demon King. Even I can tell by sensing the mana if he’s nearby…,” I observed.

At the very least, he wasn’t in this chamber. So—could he be beyond that door? Did he anticipate our move to rescue Nio and get ahead of us?

Before I could ask Yuu about it, I suddenly felt a hideous presence descending from above. I scooped up Yuu, who hadn’t even noticed, and leapt aside.

In the very next moment, a gigantic, wingless dragon—like a mountain come to life—a chthonic Earth Dragon crashed down before us. Looking up, I saw an enormous summoning circle forming overhead.

“Hey, come on—this thing’s huge! Where the hell am I supposed to cut it?” I muttered.

The Earth Dragon was on a scale incomparable to any golem; with a single front claw, it could flatten a two-story house in one swipe.

“If it kept going like that, we’d be crushed… Hey, didn’t you notice it coming?” I barked.

I expected Yuu to at least sense the forming summoning circle, yet her face was twisted as if she’d chewed on a bitter pill.

“I know this dragon,” she said coolly. “It’s the ‘Mountain Devourer Grulton’—a dragon that had been rampaging long before I ever saw the light of day.”

“That monster, huh…” I murmured. I recalled reading about Grulton in ancient texts—a beast that had existed for thousands of years, crushing mountains and forests, annihilating countless races. They say it can even disguise itself as a mountain, making it nearly impossible to detect with mana sensing. But since records say it was employed by the Demon King, it must be nearby.

Even so, here we were—facing a monstrous creature when we were supposed to be rescuing Nio.

“…Kaim, I suggest we retreat for now,” Yuu said solemnly.

I shook my head. “There’s no time for retreat. The impact from this giant’s fall has sealed the entrance. If we try to move it, we’ll get hit and end up done for.”

“But—against Grulton, not only my magic but even Asterion…” Yuu started, clenching her lips.

I patted her head with a sigh. “Are we really going to give up now after all we’ve been through? Our goals—both mine and yours—are right in front of us.”

“Kaim…” she began.

“Come on, some heroes of old used to say, ‘Everyone dies sooner or later’—even monsters like these,” I insisted.

“But how on earth are we supposed to damage it? I just can’t…” Yuu protested.

Honestly, if a mountain-like dragon suddenly appeared before anyone, fear is natural. Even if the foe is defeatable, its weaknesses and tactics suddenly vanish from view.

It’s at times like these that you have to shine a light of hope—no matter how forcibly.

“All right, can’t be helped. Let’s do this,” I grunted.

I really hadn’t wanted to, but it seemed the time had come to unleash Asterion’s full, serious power.

Pointing the tip of Asterion at the giant, I declared,
“My long life ends here. Sorry, but you’re gonna have to back off. I’m just one step away from Nio’s place.”

I drew a deep breath—スゥ—and concentrated all my will on Asterion.

“…Carry me, this body,” I murmured.

With Asterion in hand, what came next wasn’t some pretentious heroic catchphrase or a flamboyant incantation like a grand mage’s. It was nothing more than a threat.

“If you don’t lend me your strength, Asterion, I’ll discard you!” I roared.

At my command, black magical energy erupted from Asterion like writhing snakes. It slithered around my body and then tightened its grip.

“Ugh—!” I howled as excruciating pain shot through me, and trails of dark magic were seared into my skin.

At the same moment, power and mana surged through every part of my body—the very black magic that Sieg had once abandoned and even Nio found agonizing to handle. This was the dark power of Asterion, a formidable force designed to reject those unworthy. But because I had been accepted, Asterion wasn’t lending me its strength out of heartfelt loyalty; instead, it was pleading, “It hurts like hell—so please take back your threat to discard me!”

Yet this was the only way to draw out the full, true power of Asterion—a method that combined the radiant magic of hope with the rejecting darkness, regardless of why it was originally made.

“Hey, Yuu, just so you know—I won’t last long. So…” I said, my voice strained as I held the divinely glowing Asterion, its black magic flickering around it, while pain surged through my body.

“I’ll dish out as much damage as possible. After that, I’m counting on you,” I ordered.

This was nothing more than a desperate, defiant stand.