The Rightful Key

A Murim dungeon gate.

There was a time, soon after This Sovereign returned to my homeland, when I looked into the matter out of sheer curiosity. And while this world has no shortage of Martial Arts Awakeners, gates tied to Murim proper proved almost impossible to find.

The first reason was that the great guilds who monopolized the gates never properly released their dungeon intelligence. The second was that information was scarce to the point of absurdity—which itself suggested that Murim gates were, in all likelihood, vanishingly rare.

Truth be told, I had doubted the very existence of a "Murim dungeon" from the start. Hunters hunt monsters in dungeons and profit from what those monsters leave behind. But what of Murim folk? If such a thing as a Murim dungeon existed, would its people be classified as monsters—humans, possessed of the very same intellect?

After all, they ran on mana. Just as there had been nothing but dead silence when This Sovereign scattered secret manuals across the internet, the awakeners of this world would have no earthly use for a martial manual even if one landed in their laps.

So if they hunted Murim folk the way they hunted monsters, what would they even gain from it? All things considered, the questions piled up far faster than the answers.

A Murim gate, of all things...

In any case, between its rarity and the drought of information, I had assumed it would only be worth investigating after becoming a hunter in earnest. And sure enough, Unhak Jinin—hailing from Murim originally—had apparently nursed her own interest in the subject. Never did I imagine I would come face to face with a Murim-linked gate in quite this manner.

"It's this way."

"Wowaahhh..."

"Well? Impressive, is it not?"

Just as Rachel Lee's laboratory had hidden beneath an ordinary commercial building, so too did this place. Guided by Unhak Jinin, I rode the elevator down beneath the earth—and a state-of-the-art facility unfolded before me, something utterly unimaginable from the shabby three-story building above. Was it something common to all 1st-generation hunters? For some reason, the look and layout really did put me in mind of Rachel's laboratory.

Impressive, if you want to call it that.

"Hmmmm...!!!"

But looking back and forth between Unhak Jinin, a living relic of Murim, and this ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠monument to cutting-edge technology...

"As I thought, it doesn't suit you... at all!"

At that, Unhak Jinin threw back her head and laughed loud and free, exactly like a white-browed Daoist immortal straight out of an old wuxia tale.

"So you noticed? This old man merely supplied the funding, so in truth I hardly know what is what myself. Had it not been for the memories of one Seomun Eunha—that child—I could never have adapted to this world at all."

A faint bitterness bled into the pleasant laughter.

"Well... in the end, this old man is nothing more than a stranger from a very distant shore."

For all that, though, she seemed perfectly adept at handling the facility's various controls as we made our way along. Fair enough—an old codger who, out of every candy under the sun, insists on handing out red ginseng drops of all things had better know how to press the buttons in her own home...!

Of course.

In truth, Se-ah's house still had dozens upon dozens of buttons scattered about—heating, cooling, and heaven knew what else—and This Sovereign remained, months on, no closer to knowing which was which...!

It was simply that This Sovereign hadn't been back all that long. Yes. That was the reason.

And so.

The moment I stepped into the innermost chamber of the facility, an exceedingly faint ripple of mana brushed against my keenly honed qi sense.

Ssssshhh—

The air, stirred by the flow of mana, whispered like a passing breeze, and riding that breeze drifted a mana so faint it was barely there. The current moved with surprising swiftness, yet its strength was feeble beyond belief.

To put it in perspective, it was like the thin draft of cold air that seeps through the cracks of a door you've neglected to line properly against the winter chill. Every gate I had ever seen had poured out an unending torrent of powerful mana—this one was weak to the point of nonsense.

"This is the Ghost Gate this old man has kept hidden away in secret. Of course... as you can plainly see, it is not in an activated state."

"..."

A crack that did not so much as waver. The smallest crack I had ever laid eyes on, kept under the strictest guard in the facility's depths. It had taken the form of a door, and like a hole punched through into somewhere else, it was bleeding out the faintest threads of mana.

"Ever since this old man discovered this door, I have tried every method under heaven to pry it open, but..."

Unhak Jinin let the words trail off, then picked them back up with a slightly sheepish air.

"It would not budge—as though it would open for no one but the bearer of the rightful key. Every attempt failed. By all appearances, 'tis a gate that opens only under certain conditions. Though at the very least, this old man did manage to force a crack open."

"The mana... it's seeping out of it...?"

"Just so. That was the sole fruit of the endeavor. But thanks to it, this place can now be used as a training ground for Martial Arts Awakeners."

Unhak Jinin sounded quite pleased with that achievement, her voice swelling with confidence. But I could only stare, dazed, at the hair-thin gap in the door—its glow burning crimson as blood—and by then, Unhak Jinin's voice had already stopped reaching my ears.

"You may well be wondering how one makes a training ground of this... Student Yujin? I say there, Student Yujin!"

Thud. Thud. Thud.

Stepping up onto the railing, I flung my whole body into the drop below. With a whirl of motion, I engaged my lightness technique and touched down as soft as a cat falling from a tree branch.

Thud! Thud! Thud!

Forgetting my surroundings, forgetting the passage of time, forgetting the world itself—

"Haaahhh..."

A long breath, heavy with heat, spilled out into the empty air, and I walked on with my ears turned to nothing but the pulsing of the Forged Blood Art.

The Forged Blood Art—first tier, Blood Flame Realm. From the entry realm, where one could temper the blood only within the flesh, to the realm from which power could at last be projected beyond it.

Drawing out the Forged Blood Art's power as though to wring every drop of blood in my body dry, I packed it into the centers of both palms and laid my hands against the door-shaped crack.

The instant my hands met the door, I knew for certain.

I... This Sovereign... knew what lay beyond it.

"It would not budge—as though it would open for no one but the bearer of the rightful key. By all appearances, 'tis a gate that opens only under certain conditions."

What stabbed through my mind was Unhak Jinin's cool, clear voice.

The Forged Blood Art was the art I had created, as if by miracle, when my spirit transcended and I dipped the skeleton of the Blood Demon Art into the ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠will of a star. The essence of the Blood Demon Art lay in resentment itself—rage and hatred, longing and obsession, piled high from all the blood shed by the countless demonic practitioners who never reached transcendence. That demonic nature, forever stalking a successor and waiting for any chance to devour body and self alike, had been excised; the "essence" that made the Blood Demon Art the Blood Demon Art was said to be no more.

But that the Forged Blood Art's roots lay in the Blood Demon Art was a fact beyond denial. The rightful key. That meant, in a word, the Blood Demon Art. And the one who bore the rightful key was none other than the Blood Demon.

Beyond this door—

"...Cheonhyeol Geumbak."

The Blood Demon Art was nothing like the common demonic arts, the kind you mastered by memorizing a mantra and drilling it into your body. It was, quite literally, closer to a single demon-beast that could never be brought to heel. And so, age after age, it was sealed away in the underground prison of Blood Heaven Castle—bound beneath every secret art and curse its keepers could muster—until the successor of the era came to claim it. Over the long centuries, the demonic beasts and prisoners locked in alongside it had turned that place into a hell upon the mortal world.

That very place: the Cheonhyeol Geumbak.

What lay on the far side of this gate was—beyond any doubt—connected to the depths beneath Blood Heaven Castle. To the Cheonhyeol Geumbak!

Like a salmon fighting its way upstream toward the waters of its birth—now that key and master had both arrived—instinct pulled, the will of heaven pulled, the Forged Blood Art pulled. This Sovereign braced both hands, laden with its power, against the door and pushed with everything I had.

"......?"

I pushed.

"Hk—hnnnggggghh...!!!"

Pushed, I did.

"Hnngh... haah! Hah! Hrrk—gghk! Ughyaaaaaaaaagh...!!!"

The door would not open, and my skinny forearms quivered violently from the strain. The ripple of leaking mana did swell a touch stronger, but it only roiled for an instant—not the faintest sign of the door actually opening...!!!

"Grrrraaahh! Come on—!!!"

Throwing a full-blown tantrum, This Sovereign gave the mana-woven crack one solid kick—

"Ghyaaaak!"

—and met a rebound hard as a wall, seizing my fiercely burning instep as I toppled over backward.

"Ow, owowowow..."

It was the rightful key... technically speaking. Except it was the Forged Blood Art, not the Blood Demon Art—less a key that slid home in a perfect fit than one whose teeth were subtly wrong. To put it another way, the lock needed the key forced around with a little extra pressure...! And this time, at least, the problem wasn't a matter of bodily strength. The door would not open because my attainment of the Forged Blood Art simply fell short...!!!

"I say, Student Yujin... whatever are you doing...?"

"Ah—uah, w-well, you see... th-that is... i-it felt like... it might open... is why...!"

"I understand one is of an age to be curious about a special door that opens only under certain conditions, but kindly restrain these impulsive antics! You very nearly frightened the heart right out of this old man."

To talk my way past the situation somehow, I had ended up playing the part of a child undone by curiosity—but judged purely by results, there was hardly any difference, and it stung...

"Now, step back for the time being. This old man can certainly keep you safe, but this place holds far too many variables. Lingering here unprepared would be far too dangerous."

"D-Dangerous...?"

Of course, the Cheonhyeol Geumbak beyond that door was a place of boundless danger. I had just tried, as if bewitched and without a thought, ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠to open it—and it was a genuine mercy that it had refused. That place was, quite literally, a hell that had gone astray and bled into the surface of the world. And of everything within it, the most dangerous by far was the Blood Demon Art itself.

Come to think of it—what had become of the Blood Demon Art, after This Sovereign ended up like this? Unlike common demonic arts, it was a mass of resentment that moved of its own accord, and that was no figure of speech. It was the very reason This Sovereign had realized this body was completely different from before: unless one reached transcendence and broke past its limits, the Blood Demon Art would put down roots in the flesh and wait, endlessly, for the moment it could swallow its master whole.

Yet that Blood Demon Art no longer existed within my body. I had managed to forget it all this time, but if no trace of it remained within me, then it had to exist somewhere else entirely...

Just then, Unhak Jinin's voice shattered the thread of thought mid-stream.

"Oh dear—did Student Yujin's little stunt just stimulate it...? It has begun."

Fwish—

This Sovereign flinched at the energy that spiked in that instant and fell back a step, footwork carrying me away. It was the kind of pressure that roused the Forged Blood Art on its own, waking it to shield the heart meridian. Mixed into the utterly ordinary mana seeping from the gate was—when had it happened?—a thick, coiling demonic qi...!

And then—mana and demonic qi churned together, condensing into one, until they took the shape of a human figure. At the sight of that black something, I heard myself murmur.

"A... shadow?"

A human-shaped shadow, radiating demonic qi. It undulated with ill intent as it settled into a stance—a stance that looked for all the world like the opening form of a martial art about to unfold.

"That is precisely why this place is dangerous—and at the same time, precisely why it can serve as a training ground for Martial Arts Awakeners."

Martial Arts Awakeners. There was no way to hand down the mantras of secret manuals, and training alone had its hard limits. Real combat experience was the one thing truly indispensable for tempering the martial arts.

"You may not know this, Student Yujin, but the source of that ominous energy is what one calls a demonic art... At regular intervals, the 'shadow' of a demonic arts practitioner manifests in just this way. This old man, too, received a great deal of benefit from this place."

Listening to Unhak Jinin's strangely subdued voice, a thin, razor-split smile flashed across This Sovereign's lips.

Just as the Blood Demon Art differed from ordinary demonic arts, so did the Forged Blood Art differ from ordinary martial arts. It did not grow through quiet drilling alone. It was an art that tempered itself through experience—through blood boiling over and vitality overflowing. And the experience in which blood burned hottest, like flame itself, meant one thing: battle.

If the strength to open the gate was lacking, then one need only grow stronger. This place, for the Forged Blood Art—

"Khu, khuhahahaha—koff, koff! Khak! Kek, kek! Hoo... hooHAHAHAHAHA—!!"

"S-Student Yujin...? Did the demonic qi... perhaps affect you badly...?"

It was, quite simply, the greatest training ground imaginable...!!!