41. The Ultimate Weapon
"That is why I hate Rin."
With my finishing blow, the massive body of Rin, transformed into the Red Frog, turned from an already sufficient red to an even darker, blackish red.
It was a color of congested rage, perhaps best called Ancient Purple.
Her expression became primal passion itself, existing before the concept of anger was born into this world, radiating the inorganic murderous intent unique to frogs.
Shpah.
A giant tongue was shot out.
A grotesque mass of muscle, like human internal organs stretched to the limit, flew toward me.
I took that tongue head-on.
No, I smashed my fist into it like a counterpunch.
And my body shattered.
Like a crash test dummy, my abdomen burst all too easily, my upper and lower body parting ways.
The Wind Chime Blade snapped like candy art.
I was no longer combat-capable.
But I wasn't panicked.
Because I had realized it before I knew it.
No, immediately after Rin transformed into a frog, I had derived the only method to defeat this final boss.
I felt a slight pity for having to bury my beloved sister in such a cruel way, in the most miserable method in this world. However, it was clear that physical attacks could no longer contend with this strongest custom robot on Venus.
Therefore, to hurt this mighty enemy, I decided to destroy Rin's heart.
"Me..."
The frog's croak echoed.
"Don't hate me."
That voice no longer held any trace of the girl; it had turned into physiological noise inducing disgust, like the scraping of a reptile's throat, or something that couldn't be thought to originate from a living organism's vocal organs.
I nodded with just my floating upper body and declared:
"Ah, actually, that's what I intend to do. The act of 'hating' itself consumes a terrible amount of energy. So, just for this time, I decided to deliberately erase my memory."
As declared, I began formatting my memory chips.
I deleted the memory area related to Rin completely from the root directory.
Since being blown to this remote region of Venus, all the memories with Rin forcibly imprinted and burned into me—I made them all "never happened."
Then, she attempted to forcibly reinstall memory data of herself into my brain like a malicious spam advertiser.
But I am a "Made in Mars" humanoid.
We, who have survived the fierce advertising wars of Mars, are experts in counter-programs against this kind of forced installation—that is, ad-blocking.
I perfectly repelled the interference from Rin and succeeded in completely erasing her existence data.
And I obtained a weapon of ultra-low temperature, even below absolute zero.
The name of that ultimate weapon is—
Indifference.
This frog doesn't die even if boiled. The more heat you give it, the stronger it gets.
Then, you just have to cool it down.
The most powerful and quickest way to cool a target is to cut off interest itself.
To maintain thorough indifference.
I executed complete indifference toward the giant monster towering before me.
Shutting down not only memories but even parts of my recognition system.
It seems I have long been skilled at locally stopping my own functions.
While pretending to look at this giant frog with hollow eyes, I shifted the focus of my gaze slightly, keeping the lens directed at her but banishing her existence to outside my cognition.
The frog seemed to be screaming something, but audio input was off.
It was now blank.
Even the material to be described vanished from my world.
There was no need to describe it.
Like this, a time that could be called eternal, or a moment shorter than Planck's constant, simply flowed by.
Thus, after fully savoring the spacetime distortion caused by the unknown gravity called "Indifference," I gently returned my gaze to the frog.
Then, what do you know?
The Red Frog, which had boasted an Everest-class giant body, had shrunk to a size that could sit comfortably in my palm by the time my gaze returned.
I placed that pitifully small Red Frog on my palm.
In the precincts of the Reverse Flow Shrine, snow was falling, making one forget that this was scorching Venus.
The absolute zero cooling effect of the indifference I released seemed to have rewritten even the physical temperature.
Shivering, I landed on the completely frozen Blood Pond—the once seething hell. Then, sliding smoothly on the ice as if skating, I brought the frog in my palm to my mouth.
And swallowed it whole.
The frog slid down my esophagus and departed for the abyss of my body.
My goal was to rescue Oto, who was trapped inside the frog.
Swallowing it like this would mean imprisoning her in the depths of my stomach as well, but strangely, I had no anxiety.
In my stomach, there is no digestive acid like in normal organisms. There is only a powerful gastric juice named Indifference.
This gastric juice should dissolve only the target I refused to recognize—that is, the frog (Rin)—and should not hurt the target I am strongly conscious of (Oto).
It went exactly as I read.
I felt like I heard a faint death cry from the bottom of my stomach, but I processed it as noise. The frog was rapidly frozen inside my body and sublimated instantly from solid to gas like dry ice.
Ultimately, the frog became 100% gas inside me.
I expelled it vigorously from my nostrils, like a smoker exhaling purple smoke, or a rude heavy smoker.
Pshoooo.
The expelled red gas, upon touching the cold winter atmosphere, drifted aimlessly and fluffy, eventually becoming particles and vanishing into thin air.
It disappeared completely.
From my memory circuits, of course, to my sensing systems, five senses, sixth sense, seventh sense, down to the eighth sense, the reaction called "Rin" vanished from every sensor.
Eventually, the word "sister" and even its concept evaporated from my CPU.
White breath leaked from my mouth.
It was not red, nor did it have a trace of blood; it was the pure white breath unique to winter.
The white breath did not dissipate but began to form a certain shape in the air.
Taking time, each molecule was carefully reconstructed.
A familiar, mass-production type high school girl setting humanoid robot.
The moment that figure appeared before my eyes with perfect resolution, a smile naturally floated onto my face.
A smile so faint it seemed worn out from waiting, yet certain, moistened my facial muscles.
I said.
"Welcome back, Oto."
Then Oto smiled shyly, somewhat embarrassed.
Having finished the tour through my internal organs, she seemed to have literally come to know every corner of my insides.
With her blue eyes filled with immense interest and love for me—the polar opposite of indifference—shining brighter than any star in the Milky Way, she replied.
"I'm home, Kai-kun."
おわり