A full week passed since that mysterious butterfly gave me my Aperture.
Since then, I’ve managed to learn how to manipulate my Primeval Essence, the energy that took on the form of that coppery green ocean within my Aperture.
It was also called the Primeval Sea.
Primeval Essence was the key to utilizing Reverend Insanity’s cultivation system.
The closest analogue to it in Fate would be Od, the internal form of Magical Energy that directly corresponded to a Magus’s lifeforce.
Cultivation in Reverend Insanity worked by using this Primeval Essence to continuously nourish and shatter the membrane-like walls of one’s Aperture, breaking into the next realm after successfully doing so.
Unlike Fang Yuan, the protagonist of Reverend Insanity, I didn’t have 500 years worth of experience as an infamous demonic cultivator who frequently picked fights with immortals.
The closest I had was 16 years worth of bullshit and tomfoolery.
In other words, I was a complete beginner in the art of cultivation and I had no teacher beyond the vague descriptions I remembered from reading the novel way back then.
This fact didn’t dissuade me one bit as my conviction remained strong.
My Primeval Sea constantly tugged from one side to the other as I willed it against the walls of my Aperture, nourishing it repeatedly.
Maintaining this process drained a good portion of my Primeval Essence, and replenishing it back required a long rest.
As was the staple of such novels, Reverend Insanity had cultivation realms.
With me having recently gained my Aperture, I was still at the Rank 1 Initial Stage.
At this rate, I wondered how long it would be until I reached Rank 2.
Was this really a cheat if it still took decades to gain any real power?
Unfortunately, it couldn’t be helped.
The curse of worthlessness endowed upon Shinji was so strong that it even affected my special cheat.
Just like in Fate, where a Magus’s talent could be ascertained by the quality and quantity of their latent Magic Circuits, a cultivator in Reverend Insanity had aptitude that was determined by the size of their Primeval Sea.
The more their Aperture was enveloped by it, the faster their cultivation would turn out.
I didn’t really know how those guys in the novel knew the exact percentage of their aptitude, but since my Primeval Sea enveloped about half of my entire Aperture, I reckoned that my aptitude should be around 50% or so.
This meant I fell under the category of a C-grade talent, the same grade which Fang Yuan originally belonged to before he slaughtered an absurd number of his genetic relatives and harvested their blood to increase his aptitude.
Luckily for the Matou, I didn’t think there was enough of them around for Fang Yuan’s method to work in my case.
He hunted hundreds upon hundreds of his clansmen, after all.
I could try finding my mother’s family, but that left a bad taste in my mouth since they haven’t done anything wretched to me.
I had no desire to burden Shina’s soul in the afterlife by having her watch her son kill her entire family for the slightest increase in cultivation aptitude.
As if that wasn’t bad enough, I soon ran into another issue.
The cultivators of Reverend Insanity were known as Gu Masters.
By refining supernatural creatures called Gu Worms, Gu Masters were able to gain superhuman powers, abilities, and even longevity in life.
Everything in this power system revolved around Gu as a concept.
Even the Aperture and Primeval Essence existed for the sake of Gu, as they served as a mobile storage space and fuel respectively.
The problem was, how could I find any Gu in this seemingly Gu-less world?
As a Gu Master, I had the option of creating my own Gu, but even that seemed unrealistic as a resourceless infant.
Thankfully, I had a Gu.
The butterfly gave me more than just my Aperture.
It actually granted me a single Gu to start out with, one which had apparently bonded to me as my Vital Gu without the need to refine it.
In Reverend Insanity, the Vital Gu was essentially a Gu Master’s chosen core Gu that was bonded with them for life.
For a simple but crude comparison, the Vital Gu could be considered as a Gu Master’s main wife, whereas the other Gu were the Gu Master’s secondary mistresses.
The Gu Master would not only have an easier time utilizing their Vital Gu over any other Gu, but the process of ‘upgrading’ it to a higher rank via refinement would be smoother as well.
In return however, the Gu Master faced the possibility of certain death should their Vital Gu be destroyed or refined by another Gu Master.
The latter was much less likely to happen to me since I was presumably the only Gu Master in the Type-Moon universe, but I didn’t fully discard the possibility as Magi proficient in familiar-related Magecraft might be able to do something similar by imprinting their will upon my Gu.
As for the identity of my Vital Gu, it didn’t have a name—or rather, I didn’t know its name, nor its function as I always kept it dormant within my Aperture.
The only thing I knew about it was that it was a Rank 1 Gu Worm that belonged to the Dream Path, a fact that I was able to determine using my natural Gu Master abilities and meta knowledge.
Its appearance was that of a pale white snake with pinkish red eyes.
It was tiny in size, much like a thread snake, and it had the distinct head shape of a non-venomous snake, lacking the two venomous fangs that it would otherwise have.
Although they were called Gu Worms, the appearance of a Gu wasn’t necessarily restricted to insects and invertebrates.
There were even Gu that resembled human body parts and unborn fetuses.
Compared to those Gu, my Vital Gu was relatively normal.
It was said that the various shapes of Gu were erratic and random, arbitrarily derived from the unique ability each one possessed.
I wondered what my Vital Gu’s ability had to do with snakes exactly.
There must be some correlation…
The reason why I hadn’t tried using it to find out the ability it had was simple enough; I never had the chance to!
As a Rank 1 Dream Path Gu, my Vital Gu would most likely interfere with dreams in some fashion and might not have any visible effects in the physical world, but there wasn’t any real guarantee.
Since Shina always stuck around, I never dared to activate its effects, fearing that I would get exposed in doing so.
…That was until today.
Currently, my parents were getting busy.
They were in the next room over since despite me supposedly being a clueless baby, they obviously still wouldn’t do it with another pair of eyes in the same room.
Earlier, they were getting mushy like crazy and it was equally crazy awkward for me, who wanted to bear witness to none of that.
Thankfully, Shina dropped me off at my cradle and the two moved on to the master bedroom where I could hear a few repeated thuds as the bed creaked.
I guess the threat of impending death must have ignited some kind of erotic passion within their hearts.
This was only natural for humans.
When faced with overwhelming dread, their inclination to reproduce is naturally stimulated.
I silently lamented the fact that despite being a bum in terms of power and character like his son, it seemed Byakuya had a much better luck and relationship with the fairer sex.
Yet another loss for Shinji.
It would have surely made my day if I wasn’t him right now.
Regardless, this was my opportunity to finally find out what my Gu had in store.
Mentally reaching inward, I tugged at my Primeval Essence and diverted a small stream of the green coppery ocean to the Vital Gu’s way.
The little snake Gu immediately responded as it widened its beady eyes and greedily absorbed the energy.
Nothing happened.
‘Huh…?
Was that not enough?’
Humming, I sent more and more of Primeval Essence until eventually, I was almost completely depleted.
Only then did my Vital Gu activate as its red eyes glowed brightly before it intertwined into itself, forming a sideways ‘8’ by biting the tip of its tail.
The mobius strip…
this was the symbol of infinity that was often represented by Ouroboros, a coiling serpent.
So this was why my Gu was a snake!
After the required amount of Primeval Essence was consumed, I began to feel an inexplicable sense of lethargy, as though I had been awake for years on end without ever getting the chance to sleep.
It didn’t take long for me to figure out that I needed to be dreaming to make use of my Gu, and so I hastily did, shutting my eyes close as my mind and body went into slumber.
The next moment, I found myself overlooking the sleeping form of an infant.
Not my own body like I would if I were astral projecting, but another baby entirely.
‘What is this?’ I scrutinized the scene before me, observing it to be the nursery chamber of what I could only assume was a very traditionally Japanese house, devoid of any modern technology.
To my surprise, an ethereal scroll manifested before me, and written upon that scroll with elegant yet easy-to-understand calligraphy were these words…
[You were born in the Heian era]
[Your parents were of noble background, denoting you as an aristocrat]
[Unfortunately, you were born with an unusual disease]