Detect Magic revealed a faint aura from the screws... Evocation? Maybe Transmutation? It's unclear. There were some lingering auras on the walls that were harder to make sense of, but they dissipated rather quickly. No other magic seems to be present.

However, while still scanning the area, the 'cleaning crew' are surprised to suddenly notice a Minotaur in the room!

It's not visible, except in the mirror, but just having seen the thing somehow makes its presence quite overt, leaving them rather unclear as whether or not the Minotaur is physically present. More worryingly, the creature looks hungry to see them, and it is quickly approaching the reflected image of the mage overseeing the group.

Significant telepathical communications are applied and it starts to seem to Mordessa that Mr Cards is trying to out-quirk the usual of Caydenite clowns personality-chaotic adventurers.

This is of course just the surface interpretation. The second level includes the possibilities that Cards is trying to build up a specific persona for some purpose, and the possibility that they are scouting for a specific purpose. The third level contains the possibility of a double bluff and various hypotheses about Cards knowing more than they have claimed to, and doing an intentional game for an unknown purpose.

Those are quite interesting mind affecting powers indeed. Checks will be made with Detect Magic, and memory confirmations will be attempted with Detect Thoughts and asking the personnel to dig up the memories of the moment where Cards' happened to show. 

In any case, it doesn't seem paramount to increase the security right now. There's no need to add uncertainty to the situation with change.

The leading Wizard is blatantly aware of their own dispensability in the face of Chelish advantage, and a creature from another world certainly qualifies as a scientific priority, if not military. They are also aware that the common staff are even more dispensable.

Orders are shouted to try to fight and possibly capture the minotaur, if an attack happens, and a possible need for reinforcements is spoken through a telepathic link.

A couple of common soldiers move to fill the space that should be between the minotaur and Wizard, and brace for the possibly coming blow.

The Wizard casts Mirror Image, creating three illusions of themselves to make it harder to attack them.

The minotaur's approach becomes a charge, clearly unafraid to meet the soldiers head on. When it reaches where the reflections of the soldiers are, things become... confusing, even terrifying.

Everyone with line of sight to the mirror must now make a Narrow Glasswork Check, Difficulty 5.

Those who fail will perceive the Minotaur charging unstoppably through all opposition, seizing the Wizard, tearing his limbs off, and starting to eat him. Like a monster out of nightmare, nothing any of them try against it will be the slightest bit effective. They will gain 1-3 CP of Nightmares, depending on how long they managed to withstand their fear before fleeing... with the exception of the Wizard, who will gain 6 CP of Nightmares and fall unconscious.

Should anyone succeed on this check (which is 'almost impossible' at Glasswork 0), they will also perceive this, but will be able to notice that the gruesome scene is confined to the mirror, and that the only real thing about the situation is the fearful reactions of the observers... and a strange light seeping slowly through the mirror. They won't gain any Nightmares, and will instead gain a Memory of Light.

The Wizard, two soldiers, and maidservant proceed to their Glasswork checks and fail.

The soldiers are Chelish and deployed at a Worldwound fort. They are trained to be able to act in circumstances including literal Demons eating their squad leader, and experienced in situations that are quite horrifying.

They are not trained to fight unknown intangible adversaries. They have heard of shadows, but not of any incorporeal monster who can tear a 5th circle casters limbs off in one round. The wizard was the person who had a telephatic link outside the room. So nobody hears the soldiers thoughts as they change from some worry to full-on screaming. 

The maidservant is frozen in terror once the minotaur appears, but once it starts to eat into the Wizard they run, screaming, dropping all the things they were investigating in the room.

A guard posted in the Hallway sees the situation, has not heard of anything happening inside the room before the screams, and has to make a snap decision. They decide to call for reinforcements, and take a peek into the room before quickly closing the door and then planning to bar it and establish a perimeter. What does their peek show?

Two soldiers and a maidservant are screaming and running towards the door. The prone and unmoving body of the Wizard is lying in the middle of the floor, precise status unclear without a closer look. No one in the room is obviously wounded. Whatever it is the three are fleeing, it isn't visible.

(fortunately for the guard, a quick peek through the crack of the door doesn't give them a good look at the mirror)

It seems either there was some sort of internal conflict, or the Wizard was attacked and the attacker has disappeared...

"Explain what is happening!"

Maidservant: "AAAAAAAAAA"

Soldier 2: "There is a minotaur who's eating Caedius! Don't you see?!"

Protocol calls for full containment but he can't really bar the door with these people trying to scream their way out of the door. He lets them to the hallway, and immediately closes and bars the door.

"Stay here. We need to contain the hallway and plausibly the floor if the attacker was invisible. It's most likely that you were attacked with illusion magic, there is no immediate danger from this room."

The door is locked from outside and as reinforcements arrive they form a perimeter at the ends of the hallway.

Nothing else goes wrong in the time it takes for reinforcements to arrive.

For their part, Mr Cards would be much easier to track down and get ahead of if they were going in a particular direction, executing a proper search, or otherwise clearly attempting to pursue some objective. As is, they're taking a fairly random path through the fortress, turning aside to peek into various rooms, doubling back, circling around, and returning to previously-visited locations to do another lap. This would be a dreadfully inefficient strategy... if not for the way otherwise disciplined agents seem to be forgetting to report in, if they even noticed anything at all. The way this fragments and confuses the reports going up the chain seems too perfectly disruptive to be accidental, leaving Mordessa scrambling to conclusively determine a list of places where their visitor probably hasn't been, and a tentative path that they travelled that's at least five minutes out of date. Whatever memory-manipulating ability is being demonstrated, it's frighteningly repeatable. A Caydenite Song-Sorcerer would at least have the decency to run out of castings of Modify Memory after a half-dozen or so encounters!

If anyone watching was able to track and remember such a minor detail, they might spot the way Mr Cards is tossing and catching a small pair of carved dodecahedrons as they snake their way through the fortress, letting them tumble in the air before catching them upon an outstretched palm. Over the centuries, the Taimen Clan have developed procedures for handling Irrigo, and the better trained sort of White-and-Gold agent is reliably able to remember their orders and take appropriate actions in its presence. Unfortunately for the Khanate, luck has in many ways favoured Mr Cards ever since they were elevated to their current position, and the combination of Irrigo and a random walk has long proven an effective tool. If anything, it's even more effective here... though part of that is the fact that the locals clearly had no idea that Irrigo existed, and don't seem to be able to muster an effective defence on the spur of the moment.

Not that they had anything in particular in mind to try today, of course; they really are just taking a walk... and relying upon The Rose Giveth in place of verbal communication, since they don't share a language with anyone not using a translation technique... and discreetly testing the effectiveness of the music of Dahut, this far from the Zee. It really has been quite a productive walk so far!

So. What is happening and what should and should not be happening: There was an encounter in the bedroom. Possibly unrelated to Cards themselves but they might've left something there. And Cards definitely is checking out waters with their capabilities.

There will be orders to deliver Cards a message about the so-called minotaur attack having happened, and asking for an explanation, at their next convenience.

It is unclear if Cards actually wants Cheliax to increase their security investment here. If they did not spend their equivalent of an 8th circle spell for this, this is just plain humiliating.

There will be a background team, who were already investigating the earlier samples from Cards, being given mandate to figure out this d**ned capability. How does it work? Is it mind control, memory modification, or splendour? They detect thoughts and ask for investigation-useful memory and sensory data.

For the bedroom, they are waiting to hear any sounds from inside. Raise dead window allows them to wait quite patiently. If the wizard is worse off than dead, they will hear from Hell, and it is good to contain the threat.

There is also a soldier with a spyglass looking at the rooms windows from the outside. 

If they get to wait 15 minutes they will eventually send in an unseen servant as a test, with one soldier opening the door and another closing it immediately once the servant has passed the door. The servant has orders to carefully walk the room from end to end, trying to figure out if something invisible is hiding there.

As a longtime denizen of the Neath, when Mr Cards makes any statement regarding time, they are in the habit of thinking of that statement in general rather than absolute terms, as whatever audience to which their statement was addressed to may be assumed to understand the impossibility of being exact with time in Neathly matters (or more precisely, the impossibility of being correct when one elects to be exact), even when they otherwise lack the technical basis for understanding just why it is that some days seem to last far longer than others, why one's own watch usually seems to agree with the time one has experienced but seldom with any other clock, or how it is that one can occasionally spend several weeks in seclusion busy on some project before emerging to greet a friend who remembers having dinner with you the day before.

Certainly, the Treachery of Clocks generally makes the measurement of time somewhat difficult in the Neath, though the few scholars of the phenomenon generally acknowledge the problem to be with time and causality rather than with the physical timepieces. Indeed, provided that they were not made with components that fail in sunlight, Neath-made clocks are perfectly functional outside the Neath, and Ratwork Watches consistently demand a premium on the Surface... though those 'export' versions are rather unpopular in the Neath, as they entirely lack many of the more exotic non-temporal features common to such watches, which regrettably rely too heavily on exotic materials to be Surface-stable. For similar reasons, Mr Cards' own preferred watch is the Nuncian design favoured among postal workers. It is a precision tool for measuring time, and it only measures time; it is emphatically not a complex overdesigned incrementor/estimator of dozens of unrelated properties of various levels of esotericism (though it does, admittedly, come with a cleverly concealed set of lockpicks, their function does not impede the watch's ability to perform its core duty). Still, the thing they like best about their watch is that its case keeps it silent when closed (and not much louder when opened); with their ears having become somewhat more sensitive as their transformation has progressed, the inaccurate ticking of many time-measuring devices has become somewhat of an annoying distraction to them.

Still, however problematic Mr Cards' experience of time is in general terms, the words for time units that the translation effect had used had come in the strangely comprehensible form of minutes and hours with no additional warnings regarding the difference in the length of those units. Furthermore, the time estimates provided by the locals were in familiar time units instead of strangely odd fractions, as one might otherwise have assumed that a different world would have a different length of day and year. So it is that Mr Cards had felt confident in assuming that their watch would give them an accurate estimate of the length of their trip by local reckoning. Armed with that estimate, they time their return to shortly before that half-hour mark, find an unobserved moment in the loose vicinity to change back into the outfit they were wearing when they last were spoke with Mordessa, before approaching the room and the guards they had left, as if nothing at all unusual had happened over that time.

Before the 15 minutes have passed, the current guard in charge of the hallway perimeter will receive a neatly folded note:

DO: receive a MEDIUM amount of thought-increasing torture, after your shift

DO: check, with haste, keeping the door open for as short as possible (ALWAYS under six seconds), with a soldier of see insivibility, the room's content

DO NOT: plan to send unseen servants on missions without ensuring a way to check if the servant found something

KEEP the perimeter. DO NOT take unnecessary risks. DO NOT be stupid.

Following of orders is attemped. A guard with See Invisible is hasted, and they take a very fast peek into the room.

"Hope you enjoyed your break, Master Cards. The scry should be ready any minute now, and will happen in this adjacent room. The spell needs to be cast in-place which is why it was not moved to the negotiation room."

Mordessa gestures and walks before Cards, entering a door on the opposite side of the hallway from room where negotiations were had. Inside Cards can notice a local caster of magic doing gesturing and sometimes speaking over a pool of water, where an image seems to be slowly forming and taking shape. It is not yet clear enough to be very informational.

"Oh and did you happen to incidentally or accidentally leave a minotaur that can: disappear or go invisible or is mostly illusory or otherwise hard to observe, hanging around in the bedroom that you arrived in? A wizard had an unpleasant encounter and we are pinning down the possible causes."

A very fast peek into the room suggests that the only non-hidden creature currently in the room appears to be Caedius, in the same position they were reported to be in when the room was last examined. A somewhat more detailed check will be needed to determine what condition they're in, of course.

As a matter of fact, Mr Cards had enjoyed their break quite thoroughly, and for reasons entirely beyond the usefulness of their observations. They had, admittedly, experienced some difficulty in gathering meaning through the narrow channel of interrogatory understanding provided by The Rose Giveth in the absence of a common language. They might have worked through that problem better, had they spent that time on a single individual, but felt it wiser and less hostile to keep their interactions with individual members of the guards brief and inconsequential, thereby minimizing both moment-to-moment suspicions and the harm inflicted during the process. But no; though they had taken the opportunity to relieve some stress by going about their investigation in an unnecessarily exuberant manner, that all was simply business as usual.

No, the part that they had most enjoyed of their walk was the slim couple of minutes which they'd spent by an unobserved window, taking the time to appreciate the view. They'd gotten glimpses earlier, but that window had faced a spartan courtyard rather than unspoiled wilderness. After nearly a dozen years living underground, seeing only artificial and dream-lights, they could not easily pass up the impulse to linger upon the sight of blue skies, friendly warm sunlight, and living surface plants. Admittedly, the local area seems to be a rather stark tundra, with little but small scrubby plants huddled among the rocks, but it's still a form of natural beauty alien to both the Neath and to Parabola, and one which would by itself have made the whole trip worthwhile.

But they're talking to a Deviless again, a matter that rather demands more focus and attention to detail... especially since the question she asked was not one of the questions they had been expecting. They quickly guess what that question likely implies... but as a matter of course, they answer as though they did not, even as they begin to follow Mordessa.

"You are asking if I happened to leave an aggressive bipedal creature with mixed human and bovine features, of my approximate size, in the bedroom I entered when I came here?" Mr Cards raises an eyebrow slightly as they respond, some incredulity colouring their high tones, "You were with me when I was last there. There was not, to my knowledge, such a creature present when I left, and I expect that I would have noticed if there was. Nor did I take any deliberate action that would have caused such a creature to appear in that room, or indeed anywhere in your fortress."

(Mr Cards is, of course, referring to their apparent Robed size in place of their natural unaugmented size.)

"That being said," they continue smoothly, "As you are about to offer me a demonstration of your own world's information-gathering techniques, it seems fair to admit that I am not unaware of the existence of such creatures. The term 'Minotaur' is a largely mythical reference on my own world, but it is a myth with some basis in truth. Various dream-animals descended from the long-extinct Aurochs are a somewhat rare existence in Parabola, for that which exists no longer, is also that which Is-Not. Some of these have adapted to Parabola better than others, becoming predatory rather than herbivorous, and the ones whose depredations have permitted them to steal some seeming of the human form are among the most dangerous of the predatory variants. I have both seen and fought such an entity in my own Parabolan travels; as a literal beast out of nightmare, its presence would seem akin to that sort of nightmare where the hunter becomes the hunted, finding all their strength and cleverness suddenly outmatched by a far stronger monstrous being, leaving them helpless prey to be slain and devoured at the creature's leisure. In my experience, such powerful beings of the Is-Not are impossible to slay, except by first tracking them to their place of power and defeating them there in single combat. Any lesser harm than that is a mere inconvenience to an entity that is more dream than flesh... though sufficient inconvenience may at least drive a hungry predator to seek easier prey."

(They elide the fact that the Minotaur they are most familiar with is something of an ally of theirs, ever since they hatched it from an egg; it made its place of power in a tent within their war camp, from which position it can easily venture forth with the scouts of their dream-armies to prey upon the dream-scouts of opposing Parabolan armies. As such, the fight they alluded to with their Minotaur, though certainly fierce, was more akin to friendly sparring than any serious attempt by either to harm the other.)

"I do acknowledge that it does sound ridiculous by common physics to describe the situation as the Minotaur having been left there by your very own self. But shrinking and apparently the ability to carry hundreds of pounds of material are not limiting factors for a skilled administrator of conveniently leaving things where they cause almost maximal chaos."

"The fact is that a squad, actually the one cleaning the room you arrived in, was reportedly attacked by a Minotaur. No members of the squad have suffered physical harm but one of their members is quite unconscious at this point. It seems quite plausible they could be one of these beings from Is-Not."

"You described and implied earlier that beings and actors of the Is-Not interact with the physical through mirrors, right? Does the mirror need to be seen for some action to be taken by somebody who is on the other side of it?"

The unfocused visuals in the vessel of water slowly clear.

Visually a coin, in the approximate middle of the view seems to be acting as a sort of optical focus for the magical lens that the image is being viewed through. Area around the coin seems quite malformed. Bits of land seem to be affected by a morphing corruption of black and green colour. A fist-sized worm can be noticed walking past.

"Understandable that you asked, in that case," concedes Mr Cards, "But yes, mirrors are the most easily accessible gates between the Is and the Is-Not, and a large ornate silver mirror is perhaps the most convenient and memorable sort of mirror. Most attacks by Parabolan creatures target those who already asleep, especially those foolish enough to sleep before a mirror, and the harm they cause is purely mental. Rarer and more potent dream entities can also influence, distract, or terrorize wakeful watchers who perceive their forms, even from the other side of a mirror. Naturally, those entities which have possessed a living host can come and go at will, if they have suitable materials and know the way; such infiltrators are as physically dangerous as their host and as mentally dangerous as the possessing entity. But yes, sight is an important factor when interacting with mirrors. Those who cannot see a mirror are not subject to the influence of that which is behind it. I do believe I mentioned covering mirrors? A thick curtain does not make a mirror completely impassable, but it does make that mirror harder to locate from Parabola, and impossible to indirectly use. A solid and opaque covering can be used to prevent both influence and passage; it is somewhat popular to keep a mirror in a shallow locking cabinet for this reason, but even placing an unused mirror face-down is often sufficient."

(They notably omit the generally effective strategy of cracking a mirror to permit most reflection while preventing passage, as it could be rather inconvenient if they actually did this and the mirror they came through proves relevant. Nor do they describe the security tricks they employ with their own personal collection of travel mirrors, or the usefulness of tinted goggles in blocking out certain sorts of visions. These are free samples from politeness and to encourage reciprocation, not a subject-specific training lecture for paying students. If the locals want to purchase more complete information, they're free to make an offer.)

The demonstration of the information-gathering spell is interesting... using the reflective surface of water as a focus for some other image? Making an accurate image of a distant location appear thus is not quite something that Glasswork could replicate, but making an arbitrary image appear is less difficult. The small coin in the middle of the viewpoint probably isn't there by accident, and so is likely necessary to the effect... which makes the thought of accepting a large number of coins from these people somewhat less attractive. That corrupt black-and-green effect, at least, is certainly new. Admittedly, there are parts of the Neath whose precise location is somewhat uncertain, but the Treachery of Maps does not generally cause places to shift their position and nature before one's eyes. The walking wormlike creature is also interestingly different; they generally would've expected such a creature to crawl, instead keeping its midsection upright and off the ground as it waddles along... possibly a practical adaptation, if the ground is that unwholesome?

"A true image of an area near the Worldwound, I take it?" asks Mr Cards, more for confirmation than out of anything like disbelief, "That effect is rather... distinctive, and unfamiliar. How far does it spread?"

Moving the mirror to Hell should be considered. That might prove inconvenient for Cards' travel back, if it just happened so that other mirrors do not provide the same transport capability. Well, the decision of moving the mirror to Hell isn't up to her, either way.

"Right. That shall be covered post-haste and we will take care to employ these measures."

"It is true and real-time. It is too bad that the magic of scrying* only allows a small observable area around a target."

"The corruption spreads a few hundreds of miles in most directions. It gets weaker over distance, but also worsens on areas over time as they become more thoroughly corrupted, but for now the worst corrupting effects are tied down close to the center. Most of the mutated lifeforms that can be noticed originate from Abyss, the corruptions intensity being even higher there. Mortals who are judged Chaotic Evil and sent to the Abyss as judgment mutate rapidly."

*: far-seeing

Even thought the externally visible reaction has been beaten out of them, the squad leader does feel the impulse to sigh tiredly at seeing their orders. It is interesting how well contempt can travel through a telepathy-network at multiple removes from the source.

DO: Perform the below operations BLINDFOLDED and minimizing the change of seeing the mirrors reflective side

DO: Enter the room

DO: Land the mirror CAREFULLY reflective side against the floor

DO: Cover the mirror on the floor completely with a thick curtain or equivalent

DO: Utilize Mage Hand for moving the curtain

DO NOT: look at the mirror

DO NOT: break the mirror

DO NOT: try to move heavy objects by Mage Hand

after, and only after the above has been completed succesfully

DO: Mark the now-covered mirror on the floor with a LARGE SIGN stating IMPORTANT OBJECT DO NOT INTERACT

DO: Retrieve the Wizard

DO: Follow standard procedure for illusion and/or mind affecting magic afflicted casualty

The squad performs.

No external factors interfere with the execution of the squad's orders.

"A rather difficult problem," observes Mr Cards, as they peer into the revealed image, "As a matter of sheer scale, if nothing else."

They quite automatically find themselves considering how it might be resolved. It is often most straightforward and convenient to simply draw an appropriate pattern of Correspondence sigils, but the practicality of such an approach is lost at such a large scale. On the other hand, drawn sigils are only one referent to the Correspondence; the steps needed to draw any such sigil could in theory be broken down into a set of actions to be performed, likely upon a grand scale. Through the movements of armies, perhaps? No, that might be too impractical over such terrain... maybe through the flight-paths of bats? A definite possibility, but likely not without the cooperation of their fellow Masters, who would generally be unwilling to put forth such a grand effort except to acquire a new city. Even so there are other powers involved here, and the matter of what 'pen and ink' might best be used might be seen as secondary. What exactly is happening to the ground in question as the corruption spreads to it?

A well-practised motion has Mr Cards pull reach into their Robe to pull forth the Patent Scrutinizer Deluxe!, a magnifying glass which has the singular abiding virtue that everything which exists is visible through it. One of their earliest significant purchases, and still one of their favourite tools, for all that visibility of such ephemeral existences as ghost-lights, dream-fragments, and traces of past lives does not automatically convey understanding of their meanings. They bend over the scrying vessel and close one eye as they examine the edge of the edge of the corruption through the lens, automatically beginning to tweak the various jewelled knobs to better bring the image to the desired levels of focus, magnification, refinement, illumination, adumbration, embellishment, and revelation.

It doesn't take a keen observer to notice the fortune of gemstones adorning the lens; diamonds, emeralds, rubies, sapphires, and pearls. There are royal crowns worth less, even without considering whatever complex vision-enhancing effect is built into the thing.