My Vampire Little Sister

Cthulhu's body morphed into a disgusting blob of flesh and tentacles. Its immense size was enough to cover a tenth of the Moon, and its magic power was suffocating even though we were in the vacuum of Space. Its fiendish, yellow eyes pierced into my soul as it attempted to intimidate and drive me into madness.

Intense magical energy burst forth from the monstrosity, making the hairs on my skin stand. My body was involuntarily shaking, and my soul was subconsciously asking me to run away.

So this was a monster who lived for thousands, no, tens of thousands of years…

Even if it wasn't on its home planet, Cthulhu was still a mythical Demon Lord with enough energy to rival a small planet. Without my connection to the World Tree, this battle would have been impossible.

"Sora, I'm going to absorb more magic. Will you be fine?"

"A-Ah, yes! But, will your body be able to handle it?"

"I have no choice," I sighed and looked over at the Demon Lord that had reached its final form. "Against that monster, I'll need to have the magic power of our planet to stand a chance."

"O-Okay, but if you feel any irregularities…"

"Yes, I'll stop using you."

When I return from this battle, I'll figure out how to increase my vessel's capacity. But I'll have to push my Progenitor body to the utmost limits. Shaking my arm, I channelled a vast amount of magic power from the World Tree into the four rings. Creation and Life bound together as the familiar purple battle God enveloped my entire body. At the same time, like a general from mythical times, I summoned an army of mystical soldiers, each one capable of fighting against an S-rank Hunter.

However, that was just the beginning of my siege. Space warped as Cthulhu found itself wrapped in a prison of Spacetime, and without breaking my spell, it could never hope to escape. At the same time, a red beam of pure destructive light came out from my index finger and pierced through the Demon Lord's skin. 𝒇𝑟e𝙚𝑤𝙚𝐛𝗻𝐨ν𝚎𝘭.c𝐨m

Spell after spell was cast at Cthulhu, creating a vortex of magical energy that could destroy an entire country with its touch. Even at a far range, I could feel the effects of my magic spells tapping against my Aegis barrier.

But alas, even with all my spells bursting straight at the Demon Lord, Cthulhu stood firm. Flailing its horrid tentacles around, the monster emerged from my attack with renewed anger in its eyes as its damaged body healed in less than a second.

[... You forced me to show this form… The Goddess was right; we can't let you live…]

Cthulhu's voice resonated in my mind. Its voice was on the verge of explosion, and its body shook wildly. Magic power erupted from the vile creature, and an ocean of black goo surrounded the Demon Lord. The soldiers I created, entities that could easily rival S-Ranked Hunters, were instantly vapourised by the black liquid.

And when I sent another spell flying in its direction, the black goo turned into a shield, dissipating the magic spell into nothingness.

No way, does that black fluid melt magic? I'd never thought that was possible…

Instantly my mind rushed at a million miles an hour. What was the property behind the black fluid? How could it melt magic itself? Could it destroy my Aegis barrier? Innumerable questions popped up in my head, and I desperately sought the answers. Alas, Cthulhu wasn't kind enough to give me time to think.

[Die!!!]

Flying through Space, the Demon Lord dragged the ocean of black goo behind it and rushed to my location. Seeing a miniature Moon with the flesh of a Demon charging straight at me, the calm evaporated from my face almost instantly. Without even thinking, I warped myself away with the Spacetime ring and opened the distance between the Demon Lord and me.

However, the remaining soldiers still needed to make it out. When Cthulhu's black fluid touched any of my magical soldiers, they melted away like lava breaking through ice. For the first time since ascending to a Progenitor, I was dumbfounded.

Magic was useless against the mysterious black goo. Regardless of their potency, all of my spells couldn't resist Cthulhu's anti-magic.

"What on earth was that? Sora, do you have any clue?"

"No… I'd never seen such a mysterious liquid in my life! It's by no means a natural substance!"

"I see…"

Sora has seen every natural material as the Spirit of the World Tree. Furthermore, anti-magic didn't exist anywhere on the planet. While there were numerous theories about it, none have been verified to be true. And yet, I was witnessing it firsthand.

"Jin!"

"I know!"

As another tsunami was hurled at me, I teleported far away and kept my distance. Cthulhu was unrelenting. Like a ravenous mad dog, it continually rushed at me as if it had nothing to lose. Wave after wave of that mysterious anti-magic black goo was hurled at me, forcing me to make defensive manoeuvres every time.

Tch, this guy is dangerous.

As a Progenitor, I relied heavily on my magic, especially since we're in the vacuum of space. The moment I lost my magic, I would essentially be a sitting duck, just waiting for my time of slaughter.

But, there was one silver lining…

Cthulhu… Its magic power is depleting rapidly.

As expected, using a spell to counter all magic came at a hefty cost. It took me thirty minutes to deplete thirty percent of its magic power on Earth. But now, it was bleeding about a percentage point every few seconds. If I could drag out this battle, Cthulhu's magic would be dried up, and I'll win.

If that's the case…

I focused all of my magic power into my middle ring, calling forth an azure light to wrap around my hefty shoulders. Two azure wings emerged from my back, and with it, Spacetime distorted. I teleported far away and attempted to force Cthulhu into a dimensional cage. If I were against anyone else from Earth, the cage would have sealed them for eternity. But alas, I was against a Demon Lord from another dimension.

Somehow, the mystical black goo melted the Spacetime prison I'd created. Ignoring the defences of all my spells, the monster rushed straight at me and instantly surrounded me with multiple whirlpools of black goo.

"Annoying…"

Once again, I teleported myself far away. This time, however, I used the wings on my back to give me additional range and cast time. My control over Spacetime had never been this profound, and I acutely understood how far I could push my limits. Each time Cthulhu threw an inescapable prison of black substance, I would teleport away by a hair's breadth.

[Stop moving around!!!]

Over time, the Demon Lord got more impatient. It knew it was fighting against the clock and had to end the battle as soon as possible. Otherwise, when it ran out of magic power and had no means of refilling its reserves…

[I'm not stupid, Cthulhu.]

I sent a mental message back, taunting the Demon Lord.

[You're disconnected from your planet while I'm still connected to mine. It's only a matter of time before you run out of magic power. Even if you were an existence that reigned supreme in the Demon Realm, you're nothing here.]

[...]

Cthulhu remained quiet, not because it had calmed down, but the contrary. Its rage was palpable that I could feel the heat burning from its soul. The Demon Lord sent yet another wave of black goo flying straight at me like a vengeful God who sought to punish its subjects. However, I wasn't going to play Cthulhu's game for long.

BOOOOMMMM!!!

While teleporting from coordinate to coordinate, I set up various arrays connected to a magic decahedron. The points were separated far away, so Cthulhu didn't notice until it was too late. And once the Demon Lord realised it was caught in a trap, I didn't wait anymore. Sending a vast amount of magic into my ring of Destruction, I mustered up a powerful ray of crimson light with only one purpose.

Complete and utter decomposition.

Anything that ray of light touched was decomposed down to its atoms. It didn't matter if there were an impregnable shield or a massive barrier protecting Cthulhu; this one spell was to decompose anything it touched.

In shock, Cthulhu did the only thing it could; it used the black goo as protection to melt my magic. Alas, how could any fluid outrun the speed of light? Before it fully protected itself, the crimson ray kissed Cthulhu's disgusting, scaly, slimy skin, causing the Demon Lord's flesh to turn into smoke. And to recover from the damage, Cthulhu spent even more of its diminishing magic power.

Bit by bit, I was winning the battle of attrition.

Cthulhu's magic power was falling below optimal levels as less than one per cent remained. While at the same time, I was using my crimson light to ensure it stayed caged in its shell. Slowly but surely, the Demon Lord was weakening, and eventually…

[... Name.]

[What?]

Cthulhu's voice echoed within my mind once more. However, rather than rage, I felt a particular emotion I'd never thought I would feel from a Demon Lord.

Empathy and regret.

[... Name… At least tell me the name of the person who defeated me…]

The Demon Lord had resigned to its fate. Knowing that the battle was lost, Cthulhu could only bite the bullet and let its body disappear. The black goo that protected the monster stopped flowing, and Cthulhu's massive body was revealed again. However, unlike its virile state, the Demon Lord was wrinkled up and on the verge of dissipating. All it took was one more crimson ray before I could eradicate this extradimensional threat for good.

But, as one final grace, I shall give this Demon Lord peace.

[Jin… My name is Jin Valter.]

[... Jin Valter… How regrettable… If you were on our side, then…]

[On your side? I can let you live if you tell me what you know.]

Cthulhu's words faded away as it looked up at the magical decahedron in resignation.

[... Do it.]

[...]

So to the very end, this monster won't divulge the truth, huh? If that's the case…

[Goodbye Cthulhu…]

And with one final crimson light, the Demon Lord that terrorised multiple generations and reaped thousands, if not millions, of lives from humanity…

Decomposed into atoms.