Dungeon Exploration Training (2)
Dungeon Exploration Training (2)
Just as an army needed sufficient supplies and rest to sustain an offensive during war, a successful dungeon raid required time to pause and recover. Pace management was essential at times like this.
"Ten-minute break! Don't collapse on me, though!"
The moment Instructor Herlein's words fell, strength began draining from the students' legs.
They had all been in a dark space, so their fatigue was bound to be extreme.
We gathered every lantern we'd brought and piled them in the center. Then we sat in a circle around them, leaning back-to-back against each other. That arrangement also helped prevent surprise attacks from magic beasts.
"Hoo."
Once I spread a cloth on the floor and planted my rear on it, my stamina slowly began to return.
With my back pressed against Rote's, I stared blankly ahead. While I was mentally reviewing the research plan I intended to launch in earnest next week, Rote spoke to me.
"I once saw your little sister using the exact same magic as you before."
"You mean Tesla?"
"Yeah."
Rote gave a light nod.
So that Akasha or whatever could apparently use Element Operation too.
Which meant that girl also knew how to wield my 'Eightfold Way'...
...It was strange.
I could buy that the supreme unique magic 'Element Operation' already existed as a magic art, but the 'Eightfold Way' was a subordinate concept I had developed independently. The odds that someone had copied even that down to the last detail were statistically absurd.
I had no choice but to ask Vermel about this.... Where the hell had that guy gone?
[Maybe he dropped out?]
Right, we had now reached the point where your nonsense was beyond intolerable.
Even so, Vermel wasn't the type to do that. I was slow to trust people, but about that one thing I was certain.
He wouldn't have run off without a word to me without a specific reason. There had to be some circumstance.
[What if he actually did drop out?]
Then I would have to make his head fizz like carbonated water.
[......?]
Not a joke, I meant it. My most despised category of human being was 'bastards who break promises without warning.'
I'd agreed to stick with Vermel until we caught the Demon King, so if he'd fled without notice before then, beating him to death would be only right.
[...Wow.]
Well, that aside.
"Aether, are you listening?"
"I'm listening."
"So here's the thing—I think there's a useful application for that magic you used earlier."
"Where, and what kind?"
Seeing Rote whip her head around with her eyes sparkling stirred my interest. She'd apparently come up with a good idea.
"If we use your unique magic art, we might be able to identify human-type demons hiding inside the Empire!"
"...Wow."
Had I just misheard?
If anyone else had said it, I'd have brushed it off as a joke. But when it came from the illustrious Rote—renowned as a genius even among the prodigies gathered at Tillet Academy—my emotions were a tangled mess.
After that, Rote made full use of the remaining break to explain her opinion, succinct and forceful.
Her thought process, summarized, went like this.
'Tesla' was a magic art for emitting whatever electromagnetic wave I wanted. Rote accepted this 'electromagnetic wave' as a type of mana wave, and therefore reasoned that a mage could manipulate it at will using mana particles.
"So, if you propagate a high-energy mana wave to a certain point, then cause it to lose some of its energy at the location you want to observe, it might produce light that's visible to our eyes."
"Oh..."
"Magical beasts have bodies made of machinery, so if you map the mana waves transmitted by your magic, wouldn't a different picture appear compared to a human?"
Put simply, she was proposing we do something akin to X-ray imaging on magic beasts.
She'd drawn this much insight from the information I'd just demonstrated, in a world where electromagnetism wasn't highly developed.
Maybe one day this girl would become someone like this world's Madame Curie or Emmy Noether.
"What do you think?"
"It's doable."
Now it was my turn to fill in the missing pieces from my end.
...That was, if only Rosemary hadn't been right beside us.
"You two are having a fascinating conversation. Do you always while away the hours with such scholarly dialogue?"
Seeing Rosemary approach while fluttering her fan made my stomach churn. How did she manage to pop up at every opening and disrupt things, seriously.
"If the method Lady Saliere proposed is valid, we could experiment with it right away. All we'd need is the magic art Aether just demonstrated plus the auto-mapping magic art."
Wait, now this was getting awkward.
"Yeah, it does seem worth testing."
"Hey, this looks fun! Count me in!"
"...I-isn't it dangerous?"
Right on cue, the friends who'd been eavesdropping joined in.
Amid the crowd chiming in and egging us on, Rosemary hid her mouth behind her fan and lifted the corners of her eyes. The skin beneath folded into charm lines, completing the infuriating crescent-moon shape of her gaze.
[Your retreat is cut off. What will you do?]
I'd grant her one thing: she had a damn good head on her shoulders. Unless I improvised my way out of this somehow—
"All right, I'll do it. In return, Lady Blanton, how about you go first?"
"I'll be in your care."
"The mapping result will appear in black and white. When the mana wave is in the visible-light spectrum, if the wave touches metal it gets completely reflected back."
"So... if someone were a magic beast, their whole body would show up pure white?"
"Exactly."
Strictly speaking, since this differed from X-ray photography, the imaging results had to be interpreted differently.
"If most of the body is mapped white, it's a monster. If there's a reasonable amount of gray, it's a person."
We planned to verify the experimental results with only that fact in mind.
Rosemary removed her precious-metal necklace and set it down, then spread both arms and waited for me to use Tesla. What could possibly give her this much confidence?
Was she planning to reveal herself as a magic beast right here and bury everyone present?
No, that would be out of character for her. If she'd been that impatient, the Empire would have fallen a dozen times over by now.
According to what Vermel had told me, Rosemary was currently waiting for 'something.' Because of that, she'd be trying to avoid any action that might cast suspicion on her identity.
...No way.
[Eightfold Way — Third Form, Tesla]
I directed electromagnetic waves in the X-ray band and caused them to sharply decrease into visible light near her skin. Then I measured the reflection ratio with auto-mapping and rendered it onto a translucent panel as though carving a scroll.
A silhouette of a girl, perfectly matching her frame, was mapped onto my chart.
"Gray!"
"It's gray."
"Whoa, amazing. So that means she's human, right?"
Something was wrong. Very, very wrong.
According to plasmon theory, when you shine light in the visible wavelength range, metal should glitter. I'd deliberately fired visible light into Rosemary's body, so the reflected mapping result should have been white. It shouldn't have come out like this.
"My skeleton is showing up clearly. This could be used in medicine, not just for identifying magic beasts."
The possibilities were one of two things.
Either she wasn't actually a magic beast.
Or...
Magic beasts whose bodies weren't made of metal also existed.
After that, several curious students begged me to scan their bodies too, which forced me to cast the same magic art several more times. I cut the number short before the mana stored in the Hardcover Book ran dry.
Using it any further would leave us unable to handle a worst-case scenario.
Yet the heavens were indifferent.
"You should try it too, Sis."
Rosemary's urging came at once. I'd been expecting it.
I shook my head and racked my brain for an excuse.
"The light Tesla emits moves fast enough to circle this planet more than seven times in one second. Getting hit by a beam I've fired is impossible."
"You could simply place a mirror and use the reflection."
"Once it reflects off a dielectric, some of it gets absorbed or transmitted, corrupting the original data you wanted to see."
"What about making a scroll that outputs that magic art outright?"
"It's not that simple."
By mixing in the right amount of falsehood, I deflected every one of Rosemary's attacks. That was disgustingly exhausting.
The fact that I'd have to keep up this kind of mental combat going forward made me queasy. I'd honestly rather have taken a scolding from Haspelt.
...That was only a relative statement, mind you.
"What a pity."
Rosemary smirked and returned to where she'd been resting.
That was a solid blow against me. At this rate, I'd effectively handed that girl a signed guarantee of her humanity.
"All right, kids. Let's get moving again."
As we walked with the assistance of the high-grade golems Professor Herlein had created, we gradually neared the deepest part.
It didn't take long to spot a massive iron door that looked like a boss room. After all, this was a low-level dungeon, so reaching this point hadn't been difficult.
As depicted in typical RPGs, this world's dungeons had a boss and a clear reward. Since it was a low-level dungeon, I expected the reward would be paltry, but that wasn't the goal of this training exercise.
At most, maybe one drake would appear? I just hoped Rosemary wouldn't pull any weird stunts here.
That was when it happened.
Kaboom!
"Professor! The door we came in through closed!"
"What? The golems were supposed to be keeping it propped open...!"
Herlein's panic was brief; while looking after the frantic children as best she could, she slammed a top-grade earth-magic spell into the door we'd entered.
"Normally this much would've broken it..."
Generally, a dungeon's level was rated proportionally to its scale, the strength of its structures, and the strength of the magic beasts that spawned. The wall of a low-level dungeon should've been easily breakable with something like a high-grade spell.
But that, too, was the deception of an extinction-class magic beast.
"Professor—ah, in front, a magic beast..."
"What is that?!"
We were in a sealed chamber of roughly a thousand square meters. From the far side of this immense room, a magic beast with iron fangs was striding toward us.
"It's a Fenrir!!"
It was a sleek monster classified as Calamity-class, and yet just one of the countless mutts that littered the Demon King's Castle's front yard.
Looking around, I saw Rosemary naturally hide her body among the students and observe the situation like a mouse playing dead. The students were so gripped by panic that they had no leisure to spare a thought for Rosemary alone.
Thud. Thud. Thud.
The Fenrir closed in step by step. Herlein mobilized every remaining golem to protect her pupils and at the same time prepared to intercept it.
But the preparation was meaningless.
Why?
[Kreeing.]
Because this mutt had bowed its head and prostrated itself right in front of me.