A great many measuring instruments were trained on it. Analysis by visible light. Imaging by X-ray.
At the center stood a gigantic stone, glowing faintly.
This was the underground sanctuary at the center of the Holy Capital of the Prava Divine Kingdom. <The Tree> was analyzing with full intensity the enormous <Magic Stone> installed in the heart of the city.
Measuring devices using various forms of radiation, beginning with X-rays.
Imaging equipment centered on visible light and other electromagnetic waves.
A large number of mana meters placed throughout the surrounding area.
And a real-time analysis processor handling the enormous volume of data collected by all those instruments.
Once a grand subterranean temple, lavishly ornamented and beautiful, it had been damaged during the mopping-up battle that accompanied the occupation, then stripped of all decoration for the sake of the investigation. The room was packed with sensors, and cables connected to them crawled over the floor. None of its original appearance remained.
“<Iris>, are there any problems with the information analysis?”
“No problems. Noise elimination is working too. Underground is easier to measure. There’s less noise.”
“There are microwaves for power transmission flying all over the surface, after all. Still, for now we’re at least at the point where we can build a pattern map, so it’s not really a problem. If there were any other civilizations around, it wouldn’t be nearly this easy. <The Tree> having total dominance is pretty nice.”
A-class Strategic AI <Iris> was exchanging data with Asahi while conducting experiments on the city barrier.
The plan was to observe the central <Magic Stone>, believed to be the core of the barrier, by every possible means, while launching attacks that would trigger barrier deployment and recording and analyzing the resulting phenomena.
“All right, let’s start with bombardment.”
She operated the multi-legged tanks stationed on the outer perimeter and turned their main guns toward the city wall.
“Firing in five seconds. Two, one, now!”
“Barrier deployment confirmed.”
A metal shell, fired at the relatively slow speed of around 200 meters per second, slammed into the wall. At that instant, patterns of light raced across the surrounding area. The deployed barrier blocked the shell completely.
The targeted wall was left without so much as a scratch.
“Hm. <Iris>, what do you think?”
“Insufficient data. Sample size too small. If the sensor readings are correct, the volume appears to decrease slightly when the barrier deploys. But the <Magic Stone> already shows size fluctuations every time it is measured, so it could still be error.”
“Then let’s try it around a hundred times with the same impact point and the same output.”
So they started with repetition and continued their painstaking observations.
A railgun could freely adjust muzzle velocity at the moment of firing. It was ideal for this kind of repeated measurement.
Of course, no one had ever intended a railgun to be used as an observation tool.
“At the very least, it looks safe to say there really is a statistically significant change!”
“Agreed. The <Magic Stone> decreases in size when the barrier deploys. It takes more than ten seconds to return to its original size. We can infer that barrier deployment causes some degree of consumption, at least at the moment of activation.”
The sensors observing the giant <Magic Stone> from every direction were accurately recording even micron-level fluctuations. Analysis of those records had confirmed that the stone’s volume was in fact changing.
“The light emitted by the <Magic Stone> also shows slight fluctuations in brightness even under normal conditions... but it seems to get a little dimmer at the same time the barrier deploys.”
“Barrier deployment consumes some kind of energy. And that consumed energy recovers naturally.”
Whenever the barrier protecting the city deployed, the stone’s volume shrank slightly and its brightness dropped. If left alone, its volume recovered after several seconds, and its brightness returned as well.
That was the result they obtained from multiple trials.
“Hm. To disable a magic barrier, what you need is sustained damage or repeated damage. So in other words, this <Magic Stone> is functioning like a capacitor, and once it runs dry—or falls below a certain threshold—the barrier stops appearing. Something like that?”
“Under ordinary assumptions, yes.”
To test that hypothesis, <Iris> and Asahi continued attacking it with bombardment.
As a result, the following became clear:
“The records say they were not very effective against wyverns.”
The experiments against the city wall had shown that, at least for the magic barrier of this Holy Capital, laser battery attacks caused the barrier to deploy and reduced the time until barrier neutralization to a very short span.
And yet when they had fought wyverns, laser and maser attacks had produced almost no effect.
Was that due to some kind of species trait, or something else entirely?
At present, there were no comparators. They could not even begin to guess.
“This confirms that <The Tree>’s tactics up to now haven’t been wrong! It’s good that we’ve now clearly observed that if a threat organism has a barrier, you can strip it off by continuing to fire!”
“Being able to infer that there are individual differences, or species differences, is not a bad result either.”
Combat had already suggested that the barriers deployed by threat organisms differed in obvious ways between wyverns and other targets, but having another case to add to the record was still valuable.
Going forward, if they had to fight a barrier-bearing threat organism, it meant they should first measure the properties of its magic barrier.
“For now, I think that’s enough on {N•o•v•e•l•i•g•h•t} the properties of the magic barrier itself. Next, we need to determine under what conditions the barrier deploys. What happens with attacks from inside the city? There are a lot of things we still need to verify.”
“Understood. I will make a list of test items.”
They now knew that attacks from outside caused the barrier to deploy.
So then, what exactly counted as an attack? What did not? What conditions governed the distinction?
If they could solve those questions, dealing with threat organisms might suddenly become much easier.
And if possible, they wanted to reproduce this barrier deployment through the use of a <Magic Stone>.
If the properties of this barrier could be fully understood and then put to use, it would likely allow <The Tree> to increase the durability of its structures by leaps and bounds.
“It’d be best if we could use it to protect Big Sister.”
“Relying on equipment with too many unknown variables would be extremely dangerous.”
A barrier deployment system using a <Magic Stone> was undeniably attractive, but depending on a technology whose principles were unknown carried too much risk. It might fail when it mattered most.
It might even explode without warning.
If that was the case, the AIs led by <Ringo> would never allow it to be built in.
At the very least, if it was something they had manufactured themselves, they would fully understand the principles behind it. And if something went wrong, they could deal with it. Naturally, that would take priority.
Still, if the effect proved strong enough, there was a possibility it could be adopted as a first-line defensive measure.
Which was exactly why they needed to uncover its properties as thoroughly as possible—and reproduce them if they could.
“At the very least, if we can confirm that it won’t self-detonate, there ought to be ways to use it!”
“It would be good if we could make use of the wyvern <Magic Stone> we secured.”
Incidentally, after overhearing that conversation, <Ringo> hurriedly began moving <Rain Croin> out of <The Tree>, but that is beside the point.
Until Asahi brought it up, she apparently had not considered the possibility of self-detonation at all.
