Isekai Mahou wa Okureteru! (LN) - Volume 2 - Chapter SS5

Acute Mana Failure 

The ear-splitting claps of thunder finally settled down, and the still, clear night sky stretched out over the mountains. Having just defeated the demon general Rajas, Suimei was forced to wait until he’d recovered enough that he could move again. He then shouldered Lefille’s sword and picked up the small girl like a princess, and somehow made his way down the mountain road. While his heart was seized by the mix of exaltation and emptiness that often came at the end of a hard-fought battle, the still-weary girl in his arms called out to him in a worried voice. 

“Suimei-kun, are you really in any shape to be doing this?” 

“Hmm? Yeah, it’s not a problem, but… What’s up?” 

“That’s… I was just thinking that maybe you were putting up a strong front or something. I was just a little worried.” 

Lefille looked up at Suimei with a grim expression. Hearing she was concerned about him, Suimei flashed a smile. 

“It’s all good. I just couldn’t move earlier because I’d simply used up too much mana. Once I’ve absorbed enough aetheric from my surroundings, I’m as good as new.” 

“What do you mean? Used up too much mana? I’ve never heard of that leading to being unable to move…” 

“No?” 

“Using too much mana is supposed to leave you unable to use magic. Moreover, it’s not supposed to be possible to use mana down to the last drop like that. Mages are supposed to unconsciously cut themselves off to keep from fully wearing themselves out.” 

“Yeah, that’s certainly true. There’s an unconscious limit in place to prevent the overconsumption of mana, too… I see, so that’s how it works here.” 

In short, to prevent the overconsumption of mana, the human body’s self-defense mechanism would kick in before the caster completely drained themselves, and would prevent any further mana from being used. So what Lefille was saying was true for mages in this world, but the magicians of Suimei’s world had mana furnaces and were capable of using mana from within their body beyond that limit. That meant they were more capable of overspending, so to speak, which was how Suimei had fallen into the state he had earlier. Lefille then looked at Suimei with a puzzled expression. 

“So if you expend absolutely all of your mana, is that how you end up?” 

“Yeah, it’s called acute mana failure, or AMF. It’s what happens when you consume your mana to the extreme.” 

“Oh?” 

“When you exhaust your mana in a short period of time, your brain misinterprets that as a state of physical fatigue. Your blood flow, among other things, will slow and it will have an effect on the function of most of your internal organs. And then, like what happened to me, you’ll end up unable to move.” 

“It leaves you quite defenseless, doesn’t it?” 

“You’re not wrong. It’s quite a screwup as a magician, I have to say. But even what I went through wasn’t all that serious.” 

“What happens when it’s serious?” 

“The function of your internal organs slows enough that, on top of not being able to move, you end up with symptoms like spasms, nerve pain, and even vomiting blood.” 

“It’s quite a dangerous condition, I see.” 

“Even a minor case is a screwup, but severe cases can be fatal. But it takes something extreme for that to happen.” 

Though Suimei said so in a comforting fashion, it seemed to raise another doubt in Lefille’s mind. 

“So then what about those who don’t have any mana in the first place? Wouldn’t they always be in this Ay Em Eff state or whatever you called it? After all, they’re always without mana. But I can’t say I’ve ever heard of or seen anyone suffering from it…” 

To answer Lefille, Suimei replied with some wisdom from his own world. 

“People with no mana, huh? From our perspective, there isn’t anyone like that.” 

“What are you talking about? There are plenty of people who can’t use magic.” 

“No, that’s practically impossible. There’s probably just some reason they can’t manifest their mana. There’s a principle to intelligent life: all living beings that can think can process mana. So definitely, all humans have some mana.” 

“What? Is that true?” 

“Yeah. It’s a somewhat complicated topic, but… As a preamble, when it comes to the mystical and mystical locations—in other words, places where mana exists—there’s a way of thinking that says that such places exist exactly because intelligent beings believe that the mysteries in those places are mysteries. For something of an example, when it comes to creepy places, you can sense and recognize them using something other than your five senses, right?” 

“Certainly. But that’s true for everyone, is it not?” 

“That’s right. In short, all humans are able to sense such locations of power. Call it a sixth sense. And being able to sense that irregularity?in other words, the mysteries—means that the mystical exists there.” 

“But even if people don’t sense it, mysterious spaces would still exist, no?” 

It was just as she said. Those places were always there whether people were or not. It seemed very straightforward in that sense. However, from the point of view of mysticology, it was a little different. 

“That’s not quite right. If nobody believed a place to be mysterious, it would hold no power as a mystical location. If there were no people, there would be nobody to decisively determine that the mysteries exist there.” 

Lefille’s face grew cuter and cuter as she grew more and more pensive. 

“Hmm…” 

“You look like you’re not convinced.” 

“Obviously. It’s strange to say that if nobody was around, then those sorts of spaces wouldn’t exist, after all. Anyway, what connection does this have to do with our talks about mana?” 

“The fact that the mysteries are there means that humans are cognizant of those mysteries. And it means acknowledging that there are places that possess a higher degree of mystical power than others. Are we good up to this point?” 

“Yeah.” 

“So that means that something exists to accumulate the mysteries in that place. In order for that to happen, there needs to be an outside primary factor. However, just as I said before, mystical locations do not exist unless an intelligent lifeform observes them. That means, that by necessity, an intelligent lifeform would be that primary factor.” 

“Can you assert that?” 

“In order for the mysteries to be observed, there absolutely has to be an intelligent being present. And witnessing and being around these things leads to an accumulation of power that all intelligent life is capable of simply because it is intelligent and can therefore witness and observe such things.” 

“And that’s… mana, right?” 

“That’s right. So essentially, the ability to perceive the mysterious—the ability to think—is inherently accompanied by the accumulation of mana. There’s no way that it wouldn’t be. Since a location of power is always in a state where it is being observed, that proves the existence of the observer.” 

“But in order to prove what you’re suggesting, it seems like there’s so much you’re assuming.” 

“Then let me ask you this: how is it different from looking at nature and trying to rationalize it? In either case, we’re just interpreting what’s around us in a way that’s convenient, right?” 

“But…” 

“Lefille, the truly perfect equation that you’re talking about—the ultimate right answer—is something that only an omnipotent being would know. The rest of us are just slogging through one theory after another to try and get closer to it, be it in physics or mysticology.” 

“…I feel like this talk is going to drive me crazy.” 

“That’s how it goes. Mana and the mysteries are all basically metaphysical. It has a certain draw to it. People want to understand it, but the first to dive right into it and try and build a foundation for the rest of it paid the price with their sanity.” 

With that, Suimei realized he had gone somewhat off topic. 

“Well, to bring it back around, all humans possess mana. In the hypothetical case that someone truly didn’t have any innate mana, there’s the term chronic mana failure or CMF, but…” 

“Even though they don’t exist, there’s a term for it? What kind of symptoms would that have?” 

“Just think about it. Not possessing mana from the very beginning would mean…” 

“Ah…” 

“That’s how it is. Regarding that, we can only say that they don’t exist.” 

Lefille seemed to be convinced. But before long, she looked up at Suimei with a different question. 

“By the way, Suimei-kun… I’ve been wondering this for a while now, but where did you really come from?” 

“Earth. A place that the people of this world would call another world.”