"This is... quite spacious. What's a place like this doing underground?"
What Rei saw after descending the stairs was a space that could only be described as a vast underground chamber.
Compared to the darkness of the staircase, the stone materials forming the walls glowed faintly. While somewhat dimmer than the outside, it was still bright enough to survey the room without difficulty.
In terms of sheer size, it was unquestionably larger than the mansion standing above it.
In fact, it likely exceeded the entire grounds of the mansion overhead.
Naturally, that meant this underground chamber must extend beyond the property lines and into neighboring estates—a practice that would normally never be permitted.
(Does the owner of the neighboring property know about this? No, if they did, it would obviously cause an uproar... In that case, do they not know about it?)
Gazing across the vast space, Rei found himself with more questions than answers.
Beside him, three Guards trembled as they looked around.
This underground chamber was clearly colder than inside the mansion.
It was as cold as being outside... no, depending on the moment, it wouldn't be strange to feel even colder than standing out in the open air.
Only Rei, wearing the Dragon Robe with its simplified air conditioner function, seemed particularly unaffected by the cold.
"Hey, what do you think? ...I'm pretty sure the one from earlier escaped in here, too."
"Probably. But look."
One of the Guards nodded at Rei's words and pointed toward the far wall of the underground chamber.
There, just like the staircase Rei and the others had come down, was another set of stairs leading upward.
And it wasn't just one—several other staircases were visible as well.
"Where do you think those stairs lead? Given the locations, I don't think they connect back to the mansion we entered."
The three Guards nodded in agreement.
(Or rather, the light illuminating this chamber... is it coming from the stone itself? The materials seem to glow somehow. It has a dungeon-like feel to it.)
Rei had explored several dungeons before, and it wasn't particularly unusual for a dungeon itself to glow, eliminating the need for light sources.
However, that was something that happened in dungeons. Rei had never heard of such a thing in ordinary architecture.
Even if someone brought glowing stone materials or rocks out of a dungeon, the light would eventually fade.
Despite that, the underground chamber spreading before Rei's eyes appeared as though its building materials themselves were emitting light.
"...Well, it's clear that this underground chamber is abnormal in more ways than one. But what do you think it was built for?"
"If you think about it normally, wouldn't you say it's related to the Cobolt incident that's been happening?"
One of the Guards answered Rei's question.
Those words carried undeniable persuasiveness.
To begin with, Rei and the others had come here seeking clues that would lead to the mastermind behind the Cobolt incident.
Finding such a suspicious underground chamber in a place like that—expecting them not to look for a connection would be unreasonable.
"Which means something was being done here. ...Rei, can you make anything out?"
Prompted by the Guard, Rei focused his five senses—particularly his sense of smell—searching for any clues, but there was no lingering scent of blood.
Granted, while Rei's senses were sharper than normal, that was only in comparison to an ordinary human.
Naturally, that sharpness didn't rival Set's.
"...Nothing. At the very least, there's no smell of blood, so it's unlikely anyone died here."
At Rei's words, one of the Guards spoke while surveying the surroundings.
"Something to summon Cobolts was being done here, huh. If you think about it normally, the obvious suspect would be some kind of ritual or the like..."
"But even if it's a ritual, it doesn't necessarily require spilling blood, right?"
Rei could naturally hear their conversation, but as someone who supported the theory that a Magic Item was being used to summon Cobolts—a theory he half-knew was wishful thinking on his part—he couldn't bring himself to say anything about it.
"Really? Since it's a ritual to summon Cobolts, I don't think it'd be strange if they used sacrifices at least."
"Sacrifices?"
At the word "sacrifices," Rei recalled the sight he had witnessed earlier... the many corpses reduced to nothing but skin and bones.
Why there were that many corpses was something even Rei hadn't understood.
But if, as the Guard suggested, some kind of ritual using sacrifices had been conducted here, then the reason behind it wasn't entirely incomprehensible.
(Besides, those corpses had been reduced to skin and bones, but there were no other wounds on them. If they used those skin-and-bone corpses—probably the Red Cloth members—for some kind of ritual here, then the absence of any blood smell would make sense, too.)
Rei was organizing his thoughts while observing the surroundings when one of the Guards called out to him.
"Rei, you reacted to the word 'sacrifices.' Something on your mind?"
"Ah... right. I didn't mention it, did I?"
With that, Rei described what he had seen—the pile of corpses reduced to skin and bones.
Upon hearing the explanation, the Guards grimaced at the information, which was even more gruesome than expected.
"So this mansion turned out to be quite a troublesome place after all. What on earth were they thinking, pulling something like this here?"
"No... if you think about it normally, it's not that bad a choice. Doing something like this here wouldn't normally be discovered so easily. ...Well, though it was through casual conversation—mentioned in passing, really—the fact that someone told Red Cloth about this place was significant."
"Probably. To begin with, no one would normally even imagine that a place like this exists underground."
As he muttered that, Rei suddenly noticed something.
"Hey, do you think this underground chamber was prepared for this occasion? Or do you think it's been here for a while?"
'...'
At Rei's words, the three Guards fell silent in unison.
After seeing this underground space, they simply didn't know what to say.
One would normally assume it had been created for the Cobolt incident, but building such a vast underground space would require considerable labor.
It was true that many people had gathered in Gilm for the Expansion Construction, but even so, constructing an underground space of this scale would have inevitably attracted attention.
Moreover, this place was not far from the Noble District.
The Expansion Construction was taking place in an area away from here, so if a large number of workers had gathered to excavate this space, attracting attention would have been unavoidable.
(In that case, what's conceivable is... yeah, this underground space wasn't created recently, but much earlier. And not just a few months ago—possibly on the scale of years.)
Rei speculated as he looked around, but if that were the case, then various other questions arose as well.
The biggest question was, as expected, that this Underground Facility extended beyond the grounds of the mansion Rei and the others had entered, reaching into the grounds of neighboring estates.
For the owners of those adjacent mansions, there was no way they would tolerate someone expanding a space like this beneath their own property.
"Is it possible that the owners of the surrounding mansions are actually all the same person...?"
"No."
The Guard immediately denied it.
"How can you say that so definitively?"
"We're Guards. Our jurisdiction here is different, but the Noble District is still one of the most important areas in Gilm. Naturally, we've memorized information about the area from the start."
"...I see."
Being told that, Rei had no choice but to accept it.
At the same time, he was once again impressed by the Guards' capabilities.
At the very least, Rei had no intention of deliberately memorizing such things.
"In that case, what does that mean? Is it possible that the people in the surrounding mansions simply haven't noticed this underground space?"
"That's... well, I can't say it's impossible."
Though he answered Rei, the Guard wasn't quite convinced by his own words.
The underground space sat at a considerable depth, and even if the surrounding mansions had their own basements, it was conceivable they wouldn't reach this far down.
However, given that such a vast underground space existed, any significant activity here wouldn't go unnoticed by the residents above.
Thinking that, Rei suddenly realized something.
"Hey, the residents of the mansions around here... or rather, the owners, they're all different people, right?"
"Yeah. That's why I said so earlier."
"In that case, is it conceivable that someone is pulling the strings above all those residents and owners?"
Rei suggested, but the Guard shook his head.
"The owners of the mansions surrounding this one are connected to various factions—the Noble's Faction, the King's Faction, the Neutral Faction, and so on. Which means..."
"I see. That's a stretch."
"Yeah. ...Of course, it's not impossible to force that through, but..."
The most likely possibility was that the residents of the other mansions simply didn't know.
Told this, Rei looked around once more.
Creating such a vast space completely unnoticed... and furthermore, likely maintaining it for a long time—there was a profound sense of incongruity to it. And yet, given the current situation, arriving at that conclusion was unavoidable.
"In that case, for now... what do we do? There's no doubt this underground space has some kind of significance, but the one who attacked earlier is nowhere to be found, and investigating here turns up nothing else."
"...When you put it that way, you're right."
A Guard was about to say something in response to Rei's words... but in the next moment, his mouth was suddenly covered by Rei's palm.
The Guard whose mouth was sealed, along with his two companions, were about to direct questioning glances at Rei—as if to ask what he was doing—but paying no attention to them, Rei dragged the Guard toward the wall.
From Rei's demeanor, the Guards must have concluded that there was some reason he had to act right now. The one whose mouth was sealed showed no particular displeasure and quietly moved to the wall.
They moved as silently as possible... and after reaching the wall, several tens of seconds passed. Suddenly, something could be heard.
What it was became immediately clear.
"Humming?"
One of the Guards murmured in a whisper only those nearby could hear.
Yes, it was unmistakably humming.
In the mansion where Rei and the others had been earlier, the Guards and Rei had already conducted a search. Furthermore, Set and the Guards had surrounded the building to ensure no one could escape.
Despite all that, humming? Just as that question formed in Rei's mind, he felt a light tap on his arm from the person whose mouth he'd been covering. Judging that it was safe to release his hand, he let go.
A significant reason for releasing his grip was his conviction that they needed to capture whoever was humming.
At any rate, as Rei and the three Guards held their breath and remained silent... eventually, the source of the humming appeared.
The figure emerged from a location separate from where Rei and the others had descended.
In terms of distance, it was likely the mansion next to the one Rei and the others had entered to search.
When they saw that figure, Rei... and the Guards... felt as though a lead had walked right into their hands.
However, upon seeing that the humming figure was carrying a rope, and that at the end of that rope several men were tied together in a chain, they found themselves unsure of what to do.
Moreover, the men chained together said nothing, being pulled along by the one holding the rope without voicing a single complaint.
Rather, they walked as if pulled by the rope, as though they had no will of their own.
"Rei."
Rei, who had been watching the man holding the rope and the men being dragged along, was suddenly tugged by the Guard pulling his Dragon Robe and called out to in a whisper.
What is it? Rei directed his gaze toward the Guard.
The Guard's expression hardened... and he spoke.
"I recognize several of the men tied to that rope."
Being told that, Rei immediately understood what it meant.
In other words...
"Red Cloth, huh."
The Guard silently nodded in response to Rei's murmured words.