"Besides the generally known stuff like Ossuarists are parasites, they steal Arcanists powers… nothing else, really."
"Oh, wow. I thought you'd have had access to more information being that you're from a noble family and all."
"Not Ossuary knowledge. That only applies to the Arcane," Finn explained.
"Okay then, what do you know about the Arcane and Arcanists in general?" Isis asked, settling comfortably on top of a desk.
"A lot, actually. The mana cost equation, affinities, specifics of Arcanist ranks… I know a lot. What do you want me to talk about?"
"Impressive," Isis nodded, then asked, "In particular, what do you know about how Arcanists get their powers—? About why Arcanists exist at all?"
Finn frowned at the question, "For the first, that is referring to the mana cost equation: Mana cost is inversely proportional to the natural probability of the desired outcome… right? For the second question, I have no idea at all."
"Let's start there." Isis spun and leaped off the desk, walking to the board in front of the class. She wrote and drew as she spoke. "There are three types of people in our world. First are the normal average people – They take up the majority of the population. They can meither sense nor interact with mana at all.
The second are the Arcanists – The special group of people who are born with the ability to interact with mana and cast magic. They make up a small percentage of the population. Occurring once in every two hundred births.
While Ossuarists are the rarest of the rare. We are exactly like the average person in that we can neither sense nor interact with mana as Arcanists do. And of all the three types, we are the least occurring. Only one in every ten thousand births at the very least."
Finn nodded to show he understood as Isis explained.
"You explained the mana cost equation earlier, right? Now I'll explain why that is even possible," Isis continued.
"It all boils down to the density of the soul. Normal people are born with a soul density — and therefore, soul strength — that isn't enough to break into the range where interaction with mana becomes possible.
Arcanists on the other hand, are the special ones. Their soul density is just above the normal range and within the right threshold for their soul to be powerful enough to interact with mana."
Finn's eyes suddenly lit up in realization. "Wait, so is that why an Arcanist's talent at birth is so vital? Some are born at higher thresholds, and therefore they have a better start than someone whose soul density isn't as strong?"
Isis nodded. "It is also why the mana cost equation exists at all. Weaker souls need the probability of casting, say fire for example, to be high enough for their weaker souls to influence mana to actualize the effect they desire. So, you see these kinds of Arcanists carry around a lighter to kickstart a flame or something. But in the rain, you can imagine what will happen."
Finn's eyes grew distant in contemplation as he pondered more of the knowledge he naturally had of this world, inserting the new knowledge Isis was giving him.
"But wait…" Finn frowned. "Arcanists still improve in rank. That would mean their souls can grow stronger, no?"
"Yes. But in very small increments, and all still within that 'range'"
"From your words, that means there must be a range higher than the 'Arcanist range,' then? That'll be us Ossuarists?"
"Yes." Isis nodded, glad that Finn was actively following along. "Our souls are extremely dense. Way denser than an Arcanist's. Such that we are way above the threshold to sense mana at all. 'Vibrating' way higher than the mana frequency range. In fact, it would be hard to distinguish an Ossuarist from an average person… if it wasn't for the existence of Chaotic soul masses…"
"The reason why Ossuarists are called parasites…" Finn chipped in, nodding in tandem with Isis.
"You already know about chaotic soul masses. But the reason why Arcanist souls become chaotic at all is also because of their ability to sense and use mana.
The more they use their souls to 'urge' mana to bend the natural rules of the world and do their bidding, the more it also affects their souls and 'attunes' it. The thing called elemental affinity, in the case of elementals, is simply an Arcanist soul attuning to an element with more and more use of it, affecting their souls…"
Finn's attention was fully on Isis, eating every word she spoke, as it was all new to him. Despite being brought up in an Arcanist home, for some reason, no one had ever explained this in such deep detail like Isis was. Perhaps even they weren't as proficient in matters of the soul as Ossuarists were.
"And you know the danger of chaotic soul masses, right?" Isis asked.
"Entropy. The decay of the world itself," Finn supplied unhesitatingly, causing Isis to raise a brow.
"I never would've thought you would concede to that so easily. Most Arcanists… and people brought up in Arcanist homes, generally don't like to concede to that fact."
"Yeah, well. My parents weren't people to try and twist something as blatantly obvious as that. Even if most chalk it up as a natural occurrence, everyone knows chaotic soul masses latch on to things that have life, decaying and corroding mindlessly," Finn shrugged as he explained.
"They are also what cause chaos breaches and world tears that open our world up to the attack of exotic planes," Isis nodded, staring at Finn with a peculiar gaze. "Okay, now is where what I'll start to say would sound somewhat preachy, maybe?" She chuckled. "But it is the sad truth at the end of the day."
Her demeanor suddenly shifted, taking a more serious air. "Some have said we Ossuarists exist because of the world. They say we are the mechanism the world set in place to heal itself of the constant tears and corrosive effect of the anomaly that is a chaotic soul mass," she said with a grim tone.
"But if you ask me, I think that is just a load of bullshit," she suddenly cracked up in laughter out of nowhere, jarring Finn, who listened tersely.
"You'll see a lot of people like this, Finn. You can listen, but do not fall for their nonsense. They're just posers trying to claim a noble goal and rally up power themselves," she mock-spat on the floor.
"In fact, when taken to the extreme, you get cults like 'The Harvesters,' who think it is their duty to purge the world of all Arcanists—"
Isis went on to ramble for another whole minute, and by the time she was done, her face was red in anger.
Finn simply kept silent for the most of it, content to listen as Isis grew increasingly heated. It seemed her vendetta against this "Harvester" cult ran deeper than surface level hate.
Finn waited for her to finish and settle. And before he even spoke, she quickly apologized for derailing off-topic.
"Sorry…" she said between breaths, "I get so heated up just thinking about them."
"Maybe we should change the subject of discussion totally?" Finn suggested. "How about teaching me the basics of how to purge soul masses or something…?