While I didn't know exactly how old Illness-san was, a conversation I’d had with Flare-san before had confirmed she had been around for at least twenty thousand years. She had existed even before Alice established the system of the Six Kings and Peerage-class in the Demon Realm.
"Kaito-sama... are you familiar... with Single-species Demons...?"
"I’ve heard the name. They’re demons born directly from magic power, right? Like Ein-san, they’re the only ones of their kind. Beyond that, I don't really know much..."
"Yes... that is correct... Single-species Demons are... beings with no identical counterparts... even if someone else has a similar ability... However... they are still a race... shrouded in mystery... and many things about them... remain unknown..."
"Is that so?"
That was surprising. There were countless races in the Demon Realm, but since people like Ein-san had been around for so long, I assumed they were well-documented. If they were still a mystery in the modern day, they must be exceptionally rare.
"Individual differences... among Single-species Demons... are immense... Some are born as adults... while others are born as children and grow up... Their magic power and physical ability... are completely varied as well... Not only that... but the knowledge they possess at birth... also differs... Some are born with vast knowledge... while others have only... the bare minimum..."
"So, there’s no real consistency among them."
"Exactly... We group them together... under one name... but their natures are... incredibly distinct... In the latest academic societies... it has been suggested that... the information within the magic power... that converges at birth... plays a role... but the details... remain a mystery..."
"I see..."
Come to think of it, Alice had mentioned during a random chat that new types of Single-species Demons are rarely discovered these days. Apparently, they were far more common in the past. Alice’s theory was that since the ancient Demon Realm was a constant battlefield with unstable magic power, it created the perfect environment for such unique entities to manifest.
"I too... was born as a Single-species Demon... From the moment of my birth... I possessed great knowledge and... powerful abilities... My appearance... has not changed since that day... If I had to mention a flaw... my magic power amount... was somewhat low... compared to others of my rank... though by the standards of the entire Demon Realm... I was born with... a significant amount of power..."
"I can’t really imagine what that’s like. Being born suddenly with so much power and knowledge... I think I'd be overwhelmed."
"I was... certainly confused... However... I was never one to... brood over my own existence... and because I had so much innate knowledge... I regained my composure quickly... Once I was calm... the first thing I did... was verify my own abilities... My oldest memories... begin with me... testing my own existence..."
The feeling of possessing knowledge and strength from the moment of birth was something only the person themselves could truly understand.
Since I’d heard that Kuro had been the one to raise Ein-san, perhaps she was one of those who had a childhood and grew into herself over time.
"My eyes... were also a bit special... They can see... magic power in the air... even without a magic formula... I can toggle this at will... but even when the effect is off... my dynamic vision is... unnaturally high... essentially Magic Eyes... However... seeing too much is... quite exhausting... which is why I habitually... keep my eyes out of focus..."
"Ah, I see. So that's why..."
So the reason Illness-san’s eyes were always unfocused was simply that she saw too much, and it was draining.
"Using these eyes... I learned how to move my body... Because battles were happening everywhere... in the Demon Realm at the time... I used the movements and magic flow... of those I deemed strong... as a reference for my own training... I didn't have a burning desire... to be powerful... but I felt it was only... right... that I should be able to... master my own body’s capabilities..."
"Now that you mention it, Illness-san, you have a fighting style that uses your opponent's strength against them... In my world, we call that Aiki. You specialize in parrying and controlling force."
"Yes... Since I can see magic power... it is easy for me... to read the flow within my opponent... My fighting style... naturally evolved in that direction..."
It made perfect sense. If she could see raw magic power without it even being formed into a formula, she could easily predict an opponent’s movements.
I was genuinely happy to learn all these things about Illness-san that I’d never known before.
Serious-senpai: "...Hmm. Wait, I might have just stumbled onto a truth of the world. Single-species Demons are unique, full of mysteries, and almost none have been born recently. Machina said it before—Shiro used to experiment with making all kinds of biological forms in the early days of creation. In other words... isn't that exactly what this is? Seriously, is that girl the root of almost every problem in this world...?"