Chapter 9: Decisive Battle

【Third car: intruder detected. Initializing defense system.】

"This is… bad…"

The blaring alarm, the whirr of the exhaust fans, and the rapid clacking of the keyboard beneath my fingertips all collided to turn the room into a storm of noise.

Using hostages to throw the enemy off balance, drawing them into terrain that favored me, then striking not at the false location I deliberately leaked, but inside a confined train car with no escape—an ambush from which they could not flee. A perfect plan. It should have been perfect.

"They can… see the firing line…?"

And yet, reality is merciless.

The children I painstakingly created were mowed down, and the laser cannon shots—attacks that should have landed flawlessly—were dodged as though they could read their paths in advance.

Even if their appearances are crude, each of those units carries the highest-grade AI and weapon systems I can mass-produce. Under equal conditions they should be able to hold their own even against the Gehenna Discipline Committee Chair. By numbers, by individual capability, by terrain—we should have been overwhelmingly superior.

No matter how talented they are, defeating this force should have been impossible.

Should have been.

"This is beyond miscalculation… cheating… ban it…"

The cause is undoubtedly their terrifying level of coordination—and Sensei’s absurd command ability. Combined, they’ve created this unreasonable situation.

"…A3 through F3, target Sensei. G3, disrupt—ah, they broke it…"

Even when I try to crush the cause directly, they immediately shift formation to counter, collapsing my plans in seconds. Always one step short. I’ve felt that sensation more times than I’d like to admit.

The on-board defense devices—destroyed.
The deployed automata—destroyed.
The self-destruct system set between cars—somehow no longer responding.
Even sniping at opportune moments gets turned against me.

"Damn… damn, damn… this game sucks…"

I nearly slammed the desk but stopped myself at the last second. Only essential equipment sits on this table. And if I have time to throw a tantrum, then I have time to move my hands. Predict Sensei’s next move. Prepare countermeasures. If I let myself get dragged along by their pace, I lose.

I will defeat them—and I will survive.

【Third car breached. Reaching the final defensive line.】

The mechanical voice, however, delivered the cruel truth without mercy.

"We finally found you, Cleaner!"

Dodging the faux-passengers lunging at them and the lasers streaking across the air, they finally reached the last car. When the door was kicked open, the figure waiting there was a tall woman with a drooping mechanical head and a black coat—Cleaner, naturally.

"Now! Give it up! You’ve lost!"

"Lost… have I."

True enough. That may be correct. My body—Cleaner’s body—is entirely mechanical. Unlike the automata owned by Kaiser PMC, I do not possess armor capable of stopping bullets. Nor do I have the divine protection—the Halo—that shields students.

And standing before me are the four members of Problem Solver 68, who’ve destroyed countless Cleaner-made automata—and their commander, Sensei. In both numbers and quality, I am inferior.

"I see, indeed."

"Now surrender quietly and release Komori!"

Even through the cameras, President Aru’s anger was obvious.

Ah, but. President. You’re forgetting something.

Right before victory is when one becomes most careless, and—

"When did I ever say I was out of moves?"

You still don’t know my trump card.

"Eh!?"

"Hey, Al-chan! Get ready! It’s coming!"

"See? I knew she was hiding something…"

"Wait, wait, wait!? The laser cannon wasn’t the trump card!?"

I have no idea what they’re talking about, but…

"Pseudo-Mystic Replication System… activating: Benedictus Halo."

I haven’t lost yet. This isn’t over.

Now—allow me to unveil my handcrafted, first trump card.

"Watch out!"

"I-It’s so bright!"

"───Is that… a Halo?"

When the blinding light engulfing Problem Solver 68 dissipated, Cleaner stood revealed—now with a massive, distorted, half-broken Halo floating above her head. Or something that resembled one, if one were to narrate it.

In Kivotos, all students are protected by the Mystic known as the Halo. As long as their Halo exists, they survive gunfire, survive explosions. In a way, it’s one of the fundamental reasons this gun-filled society functions.

Students blessed by that Mystic are strong, durable, and at times surpass even the weapons wielded by adults. It’s no wonder the woman in black wanted one so desperately.

Naturally, all members of Problem Solver 68, being students, possess one.

In contrast, my body is mechanical—merely a construct. Reinforced with durable materials, yes, but with minimal armor to maximize mobility. In a straight shootout against weapons of equal grade, I’d lose even to a low-ranking Kaiser PMC grunt.

So how do I bridge that overwhelming gap?

"The answer… is this."

"A recreation of the Mystic…"

"Indeed. Still incomplete, but its performance is guaranteed. More than enough to pose a threat to you."

"Where did you even get something like that?"

"Obviously I made it myself."

What a strange question. Not that it matters.

"Well then, shall we begin? …No—this space is a bit cramped. Let’s open it up."

With that, I maxed out the laser cannon’s output and swept it in a wide horizontal arc.

"Kyah!?"

"Ah! The wind!"

The newly opened train interior was far more suitable for a decisive battle.

"There. Now then—let’s go all out!"

"Al! Dodge!"

"I know!"

A shot to start things off.

Naturally, they dodged with ease—Sensei had warned them beforehand.

My arsenal includes a rifle modeled after a SIG Sauer MCX, a submachine gun resembling a KRISS Vector, and a Glock-type handgun. There is no rule restricting me to one weapon. As always, I use anything that can be used—grenades, flashbangs, knives. Anything goes.

"Hiding, are we? Then have a grenade."

"! Haruka, please!"

"Yes!"

"Take thiiis!"

"A bomb—! No, a smoke grenade!"

"Al! Now!"

"N-No, it’s not working!"

"It is working! We can push now!"

…So that’s how it is. Annoying. Truly annoying. Fighting them directly makes it obvious—they cover each other’s weaknesses. And whenever I try to single one out, an unexpected attack comes from another angle.

This pseudo-Halo isn’t infinite. It has a limit.

Like a shield in a game. And unlike them, my life bar is extremely low compared to my shield. I have to end this before it runs out.

──Like this, for instance.

"…How bothersome."

"Haruka!"

"Ah───"

"One down!"

I slammed her with the butt of my gun. Even if the Halo protects her and prevents actual damage, the impact can still cause a concussion. All I need is one opening to disrupt their coordination. One of them must have gotten careless in the smokescreen and stepped too close—lucky me. This camera detects body heat. Tricks like that don’t work on me.

"Next up is that little explosives girl—no, let’s go with you instead."

"! Why!?"

"She’s coming!"

"You should place your traps somewhere less obvious."

I aimed at Kayoko, who had been firing at me from the shadows. She hadn’t had enough time to react; her guard was wide open—however—

"Guh!"

"I-I won’t let you!"

Of course it wouldn’t go so smoothly.

"…Tough one, aren’t you."

"Haruka! Are you okay!?"

"I think… I’m still… okay…!"

"Hmph… that’s not what you look like. Why don’t you rest a bit!?"

"I won’t let you!"

"—!"

A blow struck me from behind.

"I’m taking you down! We’re going to save that girl! And then all of us are going out for ramen together!"

"Heh… kukuku. Go ahead and try, Handywoman! If you think you can!!"

"………Haaaah…"

I sighed as I looked up at the ceiling.

No more gunfire echoed through my headset. Only the sound of wind.

『……』

The fight was over.

"Hah… hah…"

"Sensei…"

"………It’s… our win."

And thus, the conclusion: my loss.

『……I see.』

Left arm severed. Right-side camera nonfunctional. Leg motor disabled. My battery nearly empty. And the pseudo-Halo—total destruction.

My trump card was shattered.

Cleaner could no longer even stand. This was defeat in its most complete form—almost refreshing in its finality.

Honestly. What am I supposed to do now? Cleaner is finished. Out of business. Every last piece has been played; I held nothing in reserve. Leaving a “decisive reversal” up your sleeve is just another form of carelessness. I’m the type who uses everything from the start.

From here on, I can’t survive in the underworld anymore. News of Cleaner’s utter defeat will spread quickly. And after making such a spectacle, it’s only a matter of time before someone connects this mechanical body to the person inside.

And then, sooner or later, I’ll experience death for the second time.

…I don’t want to die.

"…Cleaner, we’ve won. As promised, release my student."

…Maybe I should just do as he says and let Sensei take me into custody? …No, that won’t work. Even if he tries to help me, they’ll figure out who was inside this body, and I’ll be punished accordingly. I hate pain. And escaping this place alive is nearly impossible. There’s no way a frail girl like me could walk alone through the Black Market and come out unscathed. Even during the last job, I made it out only because I brought an AI-equipped guard robot with me. Even then, a handful of delinquents harassed me. If I’d been alone, I’d have been beaten half to death for sure.

Checkmate. Completely.

All that’s left for me is to rot away here—th… at’s…

"…Cleaner?"

…No. No, I can’t. I can’t do that. Ethically, that’s absolutely wrong.

I know. I know it’s wrong. I know it’s something I shouldn’t do.
But it’s also…
“the only winning move I have left to survive.”

"…Huh?"

Using the last of my battery, I retrieved a single handgun from the storage compartment in my abdomen. It was an ordinary gun—nothing special.

But the bullet loaded inside was different.

"Temporary name… ‘Mystic Breaker Round’… It twists and destroys the target’s Mystic…"

Made from materials obtained through my deal with the man in black, this round was something that, in this world, could truly be called lethal—a real bullet. A student struck by it would have their Mystic shattered, leaving them unable to block it, and they would, quite literally, die.

I know I should never use something like this. That’s why, even though I created it, I shoved it into the corner of my memory and tried to forget it existed.

Why did I create it? Because I didn’t want to die. Because I didn’t want to lose. But it was supposed to be nothing more than insurance—something to calm myself down in case of emergency.

I never planned to actually use it.

"………"

But humans are weak to sweet temptations dangled in front of them when they’re cornered. Someone with a stronger will might have resisted. But I couldn’t. I couldn’t turn away from the hope whispering, “Maybe you can still survive.”

Click.

The muzzle pointed directly at the student in front of me—Aru—aimed straight at her forehead.

It was almost as if some unseen hand were guiding the barrel, whispering, “Go on. All that’s left is to pull the trigger.”

"Aru!"

"S-Sensei!? Don’t!"

Sensing something, Sensei leapt between Aru and me. But it was useless. This gun’s power had been boosted specifically to fire the Breaker Round, and its penetration was incredibly high. A grown man wouldn’t be enough to stop it; if I aimed properly, I could pierce straight through him.

And honestly, killing just one would be enough. If even one of them died, their formation would collapse. Shock would spread through the rest, destroying their focus. In that opening, I could use the remaining four rounds in the magazine to take out the others. That would be victory. A perfect line to victory.

It should have been perfect.

All I had to do was pull the trigger. Just flip the switch.

Come on. Come on, come on, come on—

"Then shoot me instead!"

『───────』

A warning tone rang out, signaling that the battery had finally died.

"Ha… hahaha…"

I took my eyes off the monitor and quietly placed the controller onto the desk.

It was over. Everything was over. Completely over.

But somehow, a part of me felt like maybe… maybe this was for the best. Idiot. If I died, that would be the end of everything. Wasn’t survival supposed to be my final objective? Idiot. Moron.

"What now…? There’s nothing I can do now, is there…"

So this is what true checkmate looks like.

"…Cleaner."

『……』

"……"

『……I admit it. I lost. As promised, I’ll withdraw.』

"Ah! That girl!"

『…Ahh, yes. I’ll release her.』

Luckily, the external speaker attached to the unit did not share a battery with the main body, so I could still speak a little longer.

"…Why didn’t you shoot?"

『……Who knows.』

Truly—why didn’t I…?

『Go on. The train’s emergency stop button is behind me.』

"R-Right! Let’s get off the train and go pick her up! Haruka! Go stop it!"

"Y-Yes!"

Shotgun-girl Haruka ran past me and headed toward the stop button. With this, the train would stop, and the story would come to an end.

However—as I’ve said again and again—reality never goes so smoothly.

"…Ah, Aru-sama."

"What? Did you already press the button?"

"N-No… um… the button…"

"The button?"

"It’s broken…"

"…Eh?"

……Ahhh… yeah. It must’ve gotten destroyed during the fight.

『…Well then, I’ll be going.』

"Eh!? H-Hey! Cleaner!?"

I fired an extraction cable from my back and made my escape. All that remained was to retrieve the unit with a drone later. As for the girls—
—they could figure things out on their own.