There was a white space—an endless, featureless void of pure white.
In one corner of that vast, boundless expanse sat a white throne.
Seated upon the inorganic throne was a man of indeterminate age. He had white hair, golden eyes, and dark circles so deep they looked like bruises on his haggard face. He was the being who had introduced himself to the world as the "Dungeon Master."
On this day, however, the area surrounding the throne was bustling.
Arranged in a circle with the throne at the apex were six seats.
These were no mere chairs. They were large devices designed to cradle the body like a massage chair. Encased in smooth, ellipsoidal outer shells that resembled cocoons or eggs, they floated slightly above the floor at an angle.
They looked less like furniture and more like advanced mechanical apparatuses. Their design wasn't rugged, but possessed an elegance born from the extreme removal of waste—the kind of sleek, scientific product one might find in a work of science fiction.
Sitting deep within these "chairs" were several women.
There were six in total, matching the number of seats.
Every one of them possessed glossy, beautiful silver hair and translucent, sky-blue eyes. They appeared to be in their early twenties, and each had features as perfectly refined as a doll's.
Close inspection revealed subtle differences in their countenances, but they were so similar that they could have passed for identical sextuplets without question.
"—Ai."
The Master spoke to the woman in the chair to his immediate right.
"Yes, Master."
"What is the magic essence concentration on the surface?"
"It is currently 4.997%."
"...To think it would exceed 5% in just over three years. I expected a more gradual ascent."
As the percentage of magic essence concentration on the surface rose, its rate of increase accelerated. The 5% mark was the first major tipping point.
Normally—had everything progressed according to the original plan—the concentration shouldn't have hit that threshold for some time.
"Since an Irregular appeared, it couldn't be helped."
"I'm aware. But what about the emission levels from the surface nations?"
"They are higher than our initial projections. As for the cause, countries like the United States, China, and Russia are leading the charge in secretly developing battle suits powered by magic stones. Some units have apparently already been deployed to their militaries....Regrettably, Japan is also conducting its own development, though formal deployment still seems far off."
"Hmph. So they’re all ignoring the treaty. Selfish, disgusting humans...!!"
"...We thoroughly explained the dangers of direct magic essence utilization when we had them sign those treaties..."
During the early days of the dungeons' appearance, the Master and his subordinates had contacted the world's governments in secret, providing various pieces of information. This included knowledge regarding the risks associated with rising magic essence concentrations.
Magic tools like magic stone generators that converted magic essence into other forms of energy, or magic-comms that utilized magic power, were problematic in the long term, but their short-term impact was negligible. However, tools that extracted raw magic essence directly from magic stones carried a high risk of causing rapid spikes in atmospheric concentration.
Because of this danger, the "Treaty on the Restriction of Direct Magic Essence Utilization" had been signed prior to the establishment of the WEO.
And yet, nations across the globe were secretly advancing the development of magic tools that utilized raw essence.
Their goal was the "battle suit"—a device meant to allow the superhuman abilities gained inside dungeons to be wielded on the surface.
There were two ways to manifest the power of the dungeons on the surface. One was to raise one's level until statuses like HP, MP, strength, intelligence, and dexterity reached a certain threshold. The other was much faster.
That method was simply to "increase the ambient magic essence concentration."
The process was easy: crush a massive quantity of magic stones to release the essence trapped within, creating a localized, high-concentration zone.
However, magic essence dispersed quickly, causing the concentration to drop. Furthermore, the sheer cost of the magic stones required for a brief burst of power made it a wasteful endeavor.
Thus, the world's nations were secretly developing battle suits. These were airtight garments, similar to space or diving suits, filled with high-density magic essence.
Standard materials couldn't contain magic essence, as the substance naturally permeated almost every material found on Earth.
However, it wasn't impossible to control its dispersion. Certain monster materials harvested from dungeons or special metals like mithril possessed properties that could block or even accumulate magic essence.
By utilizing these materials, one could create a suit that maintained an internal environment of high-concentration magic essence.
Compared to simply shattering magic stones in the open air, this method significantly reduced the amount of essence leaked into the atmosphere.
But that was merely a relative improvement; the problem of unconsumed essence being discharged after the suit was used remained unresolved.
"I understand why they’re breaking the treaty to build those suits, but..."
They were preparing for the inevitable emergence of monsters on the surface, and they were plagued by the paranoid fear that other nations would militarize their explorers. Given those factors, they likely felt they couldn't afford to ignore a tool for national defense that was so relatively easy to produce.
"If they truly understood that this stuff is more terrifying than nuclear waste or radiation, they wouldn't have treated the treaty with such contempt....Then again, if they had the brains to understand that, I wouldn't be sitting here in the first place. I suppose this is well within the scope of my expectations. They probably think it’s like leaded gasoline or CFCs—that the environment will eventually recover if they just give it enough time."
"Surely... they couldn't be that foolish?"
"Human stupidity knows no bounds. They'll keep telling themselves everything will be fine right up until the moment they go extinct. That’s just how humans are."
The Master spoke with absolute conviction. His tone wasn't forceful; it was the weary, cynical voice of someone describing a tragedy they had witnessed a thousand times before.
●◯●
While the Master and Ai spoke, the other five women in the chairs hadn't been listening in silence.
They were engrossed in their own lively, familial gossip.
"—So, I heard No. 12 got a marriage proposal!"
"No way! I'm so jealous!"
"I want a handsome guy to propose to me! I want to work on the surface too!"
"Apparently our looks are quite popular out there. I want to go outside and be pampered~"
"I don't know... I heard No. 17 has to deal with a ton of sexual harassment. She was complaining that the people she meets for work are all greasy middle-aged men or nasty, spiteful women."
"Ugh, that sounds about right. No. 5 said meeting with government officials is nothing but stress because of their selfish demands and harassment."
"Maybe being assigned as support for one of the collaborators is better than being sent to the WEO or the Japan Explorer Association? I want to be sent to a handsome guy, like No. 30 and No. 32 were~"
"That would be amazing... The 'devoted support girl.' Even a handsome explorer who’s wary at first would slowly open his heart until finally... Oh my god, yes!"
"I want a romance!"
"I bet No. 30 is having a total 'lovey-dovey' moment with her target right now."
"Wait, No. 30 and the others below her are still basically children, aren't they? Isn't it too early for love?"
"You never know! They say a girl is a woman from the moment she's born!"
"Kyaa! I'd love to see No. 30 with the face of a maiden in love!!"
"............"
Having finished his talk with Ai, the Master watched the noisy group with dead, hollow eyes.
Seeing her lord's expression, Ai cleared her throat sharply to grab her sisters' attention.
"That’s enough chatter, everyone. It's about to begin."
"Yes, sister."
In an instant, the women’s expressions shifted from playful to deadly serious.
The Master let out a heavy sigh and looked back at Ai.
"Ai, current magic essence concentration?"
"It is now 4.999%....The Second Dungeon Manifestation will commence in thirty seconds."
"Understood. Activate the system."
"Acknowledged. Activating system."
"Activating system."
Following Ai’s lead, the sisters spoke in unison.
Immediately, several holographic displays flickered into existence around the sisters' chairs, hovering directly within their fields of vision.
Shortly after, Ai began the countdown.
"Ten seconds until manifestation....9, 8, 7, 6..."
The count hit zero.
"...1, zero. Signs of manifestation detected. Report numbers."
One of the sisters replied instantly.
"Dungeon manifestation reactions detected at 128 locations worldwide."
The childishness from before was gone. Without waiting for Ai’s orders, the sisters operated their consoles with cold, mechanical efficiency.
"Sharing coordinate data."
"Commencing interference."
"Retrieving internal data."
"Conceptual Influx—Formation of Multi-layered Ruined World Structures confirmed."
"Commencing obstruction of dungeon formation."
"Executing. Limited activation of Satan. Requesting release of partial authority. —Granted."
"Transferring Gehenna's Fire from Satan to the interior of each dungeon."
"Gehenna's Fire, transferring. —Confirmed. All dungeon interiors incinerated."
"Magic essence influx into incinerated spaces confirmed. Estimated regeneration completion in 1024 seconds."
"Satan has completed resource recovery from incinerated matter."
"Establishing admin privileges for all dungeons using recovered resources."
"Deploying Black Obelisks in sequence."
"Deploying Black Obelisk. —Admin privileges for provisional dungeon 001 secured for Satan."
"002, 003, Black Obelisk deployment complete. Admin privileges secured for Satan."
"004, 005, 006, Black Obelisk deployment complete. Admin privileges secured for Satan."
"007, 008, 009, 010, Black Obelisk deployment complete. Admin privileges secured for Satan."
"—No. 5, No. 6, begin restructuring the dungeons with established privileges."
Understood. Commencing restructuring now.
"Transcribing structural data from library."
"Determining monster spawns. Applying statuses. Modifying appearance conditions. Modifying drop item tables. —Completed."
"Deploying teleportation circles to all floors. —Completed."
"Admin privileges secured up to Floor 40. Erosion by Ruined World Structures below Floor 41 has ceased."
"—Confirmed. Restructuring of Dungeon 001 complete. Moving to Dungeon 002."
Everything was proceeding perfectly.
And why wouldn't it? They had known the Second Dungeon Manifestation was coming and had meticulously prepared to bring every new dungeon under their management.
Failure was not an option.
Ai and her sisters calmly brought the dungeons under their heel one by one.
Then, as the count passed one hundred—872 seconds since the start of the manifestation—it happened.
"—!? Transfer reaction detected in Dungeon 121!"
An Irregular struck.
Something had been transferred from the outside into a regenerating dungeon that was not yet under their control.
"Report!"
"The objects are—massive quantities of magic stones!!"
"!? Detecting a second transfer reaction! This is—an attack on the transferred stones!"
"Magic stones destroyed! Magic essence is being released!"
"Magic essence concentration in Dungeon 121 is spiking!! Regeneration speed is accelerating!"
"Estimated regeneration completion within twenty seconds!"
"We can't do it! We won't get the Black Obelisk deployed in time!!"
The dungeons had been regenerating gradually, and the Master’s team had planned to use that time to establish privileges and restructure them to their liking.
It had been going perfectly until this anomaly.
Dungeon 121, which was already mostly formed, gorged itself on the massive surge of magic essence, slashing its regeneration time.
A window of over two minutes was instantly cut down to less than twenty seconds.
Worse yet, it was a dungeon they hadn't even started on. There wasn't enough time to stop their work on the others and secure this one before it finished.
Ai looked to the Master, her voice almost a scream.
"Master!! Your orders!!"
"Those parasites...!!"
The Master roared in fury, realizing that this Irregular was an act of human sabotage.
He gripped the armrest of his throne with enough force to crack it, but he swallowed his rage in an instant to give his commands.
"Use Gehenna's Fire again—no, it won't make it!! Full activation of Satan!! At least overwrite the slime drops!! Do NOT let it drop a Skill Seed!!"
"!!?"
Ai and her sisters froze for a heartbeat.
Even for a moment, the full activation of Satan carried an unthinkable risk. They had already fired 128 bursts of Gehenna's Fire. If they pushed it further with a full activation, there was a chance the dormant Satan itself would wake up. If that happened, it was game over. Every human, animal, and even the sisters themselves—everyone except the Master—would be annihilated.
But they were not designed to disobey their lord.
They immediately moved to execute the command.
"Full activation of Satan confirmed!"
"Activating Skill Seed!!"
"Forcing interference with Dungeon 121!!"
"Overwriting slime drop items!! —Completed!!"
"Dungeon 121 has manifested on the surface!!"
"............"
A heavy silence fell, a mixture of relief and lingering dread.
With a somber face, Ai addressed her master.
"Mas-ter... We avoided the absolute worst, but..."
"............Dammit."
Now that the dungeon had manifested on the surface—meaning its entrance was fixed to the terrestrial world—they could no longer use Gehenna's Fire to incinerate it and restart the process.
If they tried, the fire would backflow through the entrance and incinerate the surface world, causing catastrophic damage.
Thus, to bring this "Unmanaged Dungeon" under their control, their collaborators—led by the likes of Obito—would have to clear it floor by floor and plant Black Obelisks manually, just as they were currently doing for everything below Floor 21. It would have to be done by the hands of explorers.
The only saving grace was that the clearing process wouldn't be as difficult as what Obito had endured. Because it was an isolated Unmanaged Area, everything up to Floor 40 would be locked into a "narrow zone" typical of a single dungeon's size.
But even so...
"They just won't stop ruining my plans...!!"
The Master spat out the words with pure venom—but he regained his composure in the next breath.
"No, we'll deal with that later. Ai, hurry and finish seizing the other dungeons!!"
"Understood!"
Over the next two minutes, Ai and her sisters resumed their work. They succeeded in bringing every single newly manifested dungeon under their management—with one lone exception.