The Extra Who Was Fated to Die
Steam slowly rose from the soup bowl on the dining table. A miso soup that was neither clear nor cloudy, the familiar arrangement of side dishes, a bowl of freshly scooped warm rice.
The scene before my eyes was no different from yesterday.
Father was, as usual, staring at research logs on his terminal while mechanically bringing rice to his mouth, and the dining table remained submerged in silence like a programmed routine.
But somewhere deep inside me, something was stirring as if suppressed.
And the cause of that sensation was Yuzuki sitting across from me.
She was quietly sipping her soup.
Without a word. Without any emotion.
Yet between that silence, the voice from last night came back to life.
『Yuuto… you piece of trash… you perverted bastard… How could you do that to your own little sister…』
The low, suppressed moans of Yuzuki buried in the pillow, her ragged breathing, and the unfamiliar curses that had slipped from her lips.
Yuzuki wore a face that suggested nothing had happened, but I knew. I knew what kind of voice she had used to call my name while drenched in sweat on that bed.
That was why my gaze kept drifting back to her. Even now, my heart pounded so violently I thought I might lose my mind.
Then—
“What are you staring at? Aren’t you going to eat? We’ll be late for the Academy.”
Yuzuki lifted her head, chopsticks in hand.
Her jawline tilted slightly toward me, her eyebrows sharpening with irritation.
It was the familiar, annoyed tone I knew so well from Yuzuki.
But in that instant, I remembered again.
The sight of her panting and muttering my name last night.
Even the way she held her chopsticks while meeting my eyes now felt like an extension of those fevered fantasies.
I swallowed a groan.
I’m losing it…
From the moment I woke up, it felt like something had possessed me. My head was such a mess that self-loathing crept in over how things had come to this.
At the same time, I couldn’t help wondering.
Was everything that had happened truly born purely from my Coupling?
Even if she had sensed my unconscious emotions or thoughts through the neural link, was that enough to make Yuzuki act that way? To masturbate while calling out her brother’s name?
…Shouldn’t she hate me for it?
Naturally, common sense regarding family relationships was no different in this world.
Which meant Yuzuki and I were forming an utterly abnormal bond.
Of course… it was better than her hating me. But the fact that this wasn’t normal either left me horribly confused.
Or perhaps the emotional sharing through Coupling was far more powerful than I had imagined?
While I sat there holding my chopsticks, lost in thought, Yuzuki finished her meal in those few minutes.
She rose quietly, glanced over the table, and silently cleared the dishes without a word.
As she headed toward her room, she paused and turned back to look at me.
“I’ll go change first, so eat quickly.”
With only those words, Yuzuki vanished into her room. The hem of her pajamas swayed lightly, and her retreating figure showed no visible tremor. Somehow that made it feel even more unsettling.
What on earth was she thinking right now?
With Yuzuki gone, only Father and I remained at the table.
I swallowed a spoonful of rice and spoke in the most casual tone I could manage.
“…Father. I heard in yesterday’s lecture that if the Coupling threshold exceeds eighty, emotional sharing becomes possible. Is that correct?”
Father looked up from his terminal. His expression remained indifferent as always, yet a faint spark of interest flickered in his eyes.
“Mm. That’s right.”
A short answer. But there was a careful weight at the end.
I set my chopsticks down and pressed further, choosing my words cautiously.
“Then… is it possible that it’s not just ‘reading’ emotions, but also being influenced by the other person’s emotions?”
For a moment, Father’s gaze froze.
He set his spoon down and stared at me quietly. His eyes narrowed, and he seemed to sink into thought a beat late. Finally, he spoke in a careful voice.
“…It is. There have been reported cases. Especially when emotional sharing deepens past the threshold, Emotional Resonance can occur.”
Father’s words quietly confirmed my suspicions.
Then he continued.
“For example… take Sakuragi Luna.”
I lifted my head at once. It was a name I couldn’t ignore.
Father spoke slowly.
“Luna is a girl with unusually strong killing intent toward Outers. She may seem cheerful normally, but the moment she enters the cockpit, she becomes someone else entirely. She glares at the enemy with eyes that look ready to tear them apart.”
His tone carried a strange mix of coldness and awe.
“That emotion transfers directly to her partner during synchronization. In the last test, her partner suffered insomnia and hypersensitivity for quite some time. Not from battle feedback, but because he had resonated with Luna’s murderous intent.”
I swallowed hard.
His words meant that a partner’s emotions didn’t simply flow—they could burrow into the other’s instincts and impulses.
I had vaguely known about Luna’s trait. In the anime she had been an observation subject in the lab for that very reason.
Every battle, her partners complained of excessive stress and eventually requested changes. It was one of her character settings and had left quite an impression.
But I had always thought of it as simply her special trait.
Until now.
I never imagined the same kind of characteristic might exist inside me.
Cold sweat trickled down my spine. The realization that something had gone terribly wrong slowly seeped through my body.
For now it had only affected Yuzuki, but what would happen if I paired with other partners later?
If I unknowingly leaked my emotions every time I Coupled? If the same thing that happened with Yuzuki occurred again, how could I possibly handle it?
My grip on the chopsticks tightened unconsciously.
At that moment, Father spoke again.
“…The reason I stopped your Coupling with Luna yesterday was exactly because of that.”
His eyes narrowed as he continued, firm yet cautious.
“Luna’s emotional feedback is abnormally intense. It isn’t just killing intent—the way it invades is abnormal. If you were to Couple with a girl like that while completely defenseless… it could be dangerous.”
His tone suggested genuine concern, not mere precaution.
Something in my chest tightened at his words.
I asked carefully.
“…Father, knowing all that, have you never considered that I might be capable of influencing others the same way Luna does?”
Father averted his gaze for a brief moment. That short silence said more than words ever could.
“…I have considered it.”
The quietly added words sent a chill racing down my back.
Really, this man was no ordinary parent.
“I even asked Yuzuki directly yesterday. Whether she felt anything different after the Coupling.”
“Yesterday?”
“She said she hadn’t noticed anything in particular. In truth, these are only a few reported cases. We cannot say with certainty that emotions will unconditionally resonate…”
I simply stared at my spoon, listening to Father’s answer. Even the warmth of the miso soup lingering in my mouth felt distant.
Yuzuki had hidden it. She had deliberately withheld her current condition from Father.
…She had no choice.
How could she possibly say it?
No matter who she was, even Yuzuki… it was not something she could speak aloud. Especially not to Father.
After the conversation with Father, we each finished our brief preparations in our rooms and left the house.
Naturally, on the way to the Academy there was no real conversation between Yuzuki and me.
A lukewarm silence clung to us the entire time.
Heavier than the morning air, and strangely sharper than the noise of the train.
Today, of all days, the train was unusually crowded.
As passengers poured in one after another, the two of us ended up pressed close together just to secure a spot.
Fearing Yuzuki might stagger under the surging pressure, I unconsciously spread my arms, creating a barrier between her, the wall, and the crowd.
Like a shield protecting her from the relentless waves of people.
It felt like the bare minimum I could do as her older brother right now.
Still, the pressure was unavoidable. Yuzuki caught her breath for a moment, then spoke in a small voice.
“You don’t have to go this far…”
Her slightly lowered head carried a strange mix of embarrassment and gratitude.
I answered shortly without turning my head.
“It’s fine. I’m doing it because I want to.”
“…Okay.”
After that brief exchange, silence returned once more.
It was exactly then.
Warning. An Outer reaction has been detected in close proximity. The train will stop immediately. All passengers, please remain in your seats.
The moment the announcement ended, a heavy thud reverberated from outside.
The entire car shook dully, and the anxious breathing of the passengers filled the space.
—What the hell, an Outer?
—Huh…? Why an Outer?
The whispers began to spread like smoke.
Then the subway jolted again. The pressure between the tightly packed bodies suddenly spiked.
Shoulders and arms shoved against us, and the crowd’s body heat crashed over us.
Yuzuki staggered as if about to be slammed into the wall.
I reflexively grabbed her shoulder and pulled her tight against my chest.
Her body, now nestled in my arms, trembled noticeably.
The tips of her hair brushed beneath my chin, and her breath seeped through my collar.
People continued colliding behind me, but in front of me there was only Yuzuki.
Amid the ongoing chaos, the train shook once more. A screeching noise rose from the floor, followed by the sound of air warping somewhere beyond the windows.
I turned my head instinctively.
And in that instant, beyond the train window, I saw the air cracking like thin glass.
A glittering rift spread through the sky outside, and from that gap something like a black membrane burst inward.
Beyond the rift, a distorted silhouette crawled upward. A mass whose shape could not even be properly discerned moved as if devouring the boundary of space itself.
A shell like rotted flesh. Squirming curves and an eerily swift presence.
It was an Outer.
I stared at the monster emerging from the rift, forgetting to breathe.
A world where Outers existed. I never imagined I would confront that threat so close.
Of course I had known the danger of Outers was always touching reality in this world.
But even with Yuuto’s memories, this was the first time seeing one directly. In truth, all I had ever seen of an Outer’s appearance was through anime staging.
“An—an Outer?!”
“What the hell is the Defense Agency doing?! How could a dimensional rift open this close?!”
The halted train. The moment the Outer’s form became clearly visible outside the windows, the passengers’ panic swelled beyond control.
Originally, Outers were only supposed to appear in the dimensionally vulnerable zones designated by the state.
Precisely the areas known as Rift Zones.
To control unpredictable rift occurrences, every nation had deliberately created vulnerable points likely to spawn rifts, inducing their formation there and deploying Dracores in advance to maintain a defense system.
Thanks to that, most residential districts had been considered safe.
But the rift before us had formed inside a residential area.
Far too suddenly.
And I knew this situation all too well.
I had no choice but to recognize it—because this was exactly why, in the anime, the characters had begun being sent into real combat earlier than scheduled.
The sudden appearance of rifts across the entire country had forced even students to participate in actual battles, forming the main storyline of the animation.
Perhaps.
The early dialogue that had been lightly brushed off as “Rifts starting to appear nationwide” was now becoming reality right before my eyes.
“…Ah.”
My breath stopped. In that moment my mind pounded wildly, as if realizing something horrific.
A memory rose with unnatural clarity.
The early part of the animation.
Short subtitles had flowed across a white screen.
At the time I had brushed it off without much thought.
I had assumed it was nothing more than a narrative device to kick off the story. The death of an extra whose name never even appeared.
Yet now, like a fear that stole my breath, that scene revived vividly in my mind.
…No way.
That one-line victim whose face and name never appeared…
The casualty from the anime’s early episodes that I couldn’t even remember…
Could it have been Yuzuki?
The moment my thoughts reached that point, my throat tightened as if my breath would be cut off.
And right then.
BOOM.
With an explosion, the train shook violently. My vision scattered instantly. A dull pain spread from my shoulder slamming into the wall, and my ears went deaf.
Eventually every sound grew distant and my mind went blank.
The last thing I felt in that moment was Yuzuki screaming inside my arms.