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In the sky, thin clouds were dyed the color of the moon they were supposed to be hiding. My eyes were drawn to it, and I kept watching until the moon escaped from the clouds. Just as the moonlight began to settle in my eyes, I looked down at Biwashima.

After a moment, Biwashima parted lips wet with saliva from where she’d licked them.
"Senpai, what is it you're trying to tell me?"
"That someone like you, Biwashima, who gets fired up about changing the world and even resorts to murder, is the *real* heretic. And I hold a certain degree of respect for you, Biwashima. Killing someone for a reason like that… it's not something most people can do without falling into some solitary religion. It's true, from your perspective, the world must seem full of people lacking ambition."
Like those who’ve made a habit of killing people.
Or a kid who accidentally killed someone they never meant to harm.
Or someone who killed their parents just to survive.
Most people *do* have a sense of constancy, though.
"Biwashima."
[...]
"Let's assume, hypothetically, that you *didn't* do it. Yoshihito, the 'defiled one,' died and disappeared. Did your world change, even a little?"
Biwashima bit her lip and didn't answer. Apparently, there hadn't been any visible change yet. How frustrating for her, just when things were about to get started. But Yoshihito probably felt the same way right before he died, so let's call it even, nice and friendly like.
"Biwashima's world probably won't feel like it's changed unless almost everyone else in it dies. If you went as far as a depopulated area or a ghost town, you'd probably feel how deserted it is, at least."
"That sounds... utterly desolate."
Biwashima let slip a moment of weakness regarding the recklessness of her plan. Her eyes seemed to dart back and forth, looking somewhat flustered.
"Probably. Oh, and also, I hate to undermine your whole foundation here, but *my* world is plenty broad. There are lovely girls out there, beautiful young women, who live in a world where they only recognize themselves and one other person, you know. There's always someone higher up." Not that I'd say who.
Well, Biwashima was now exhausted by the debate. Her eyes seemed to narrow sleepily.
Good. This way, when Ichimiya makes her move, Biwashima likely won't fight back or make a scene, and we can expect swift processing.
Easily overturning my assessment, Biwashima murmured, seemingly out of nowhere.
"Senpai... do you, like, bully elementary schoolers?"
"...Hey, Beautification Committee member, are you moonlighting as a modern-day Urashima Tarou?"
What kind of shift in topic is that? And yet, she wasn't entirely off the mark. My past includes helping kidnap Kouta-kun and Anzu-chan, and lightly verbally cornering Itsuki.
"No, I'm just quite vexed at being lectured by a fellow student, albeit one year older, from such a superior perspective, so I thought I'd try to make you squirm a little."
"Hmm, is this that childhood symptom where you want to be mean to the kid you like?"
"Why don't you just die?"
There was clearly no question mark intended there; it was a recommendation.

Biwashima stubbornly refused to lower the wall between us. By all means, I hoped she'd maintain it until the very end.
"I have something to tell you that might make Senpai squirm, and hopefully, maybe even release me from these bonds. Consider it thanks for the lecture."
Acting entirely in her own self-interest, Biwashima began to speak.
"It was about a week ago, on the way back after going around town with Ichimiya. I went to this hangout spot I know for stray cats, and *she* was there."
Biwashima paused dramatically, drawing it out. And then,
"There was an elementary schooler dissecting a cat."
Hey, that's my sister. The phrase "elementary schooler" just solidifies my conviction, doesn't it?
"Maybe that kid is the one who killed Souda-kun, and the dogs and cats too. She had a nasty look in her eyes."
Biwashima stated it nonchalantly.
"You're the one who committed the animal slaughters before Yoshihito, aren't you?" Biwashima plugged her ears by humming.
I was certain, at least, that my sister wasn't the culprit for *those*.
After all, leaving the entire carcass at the scene? That's unthinkable given my sister's motives. She would definitely have butchered the edible parts and taken them home. Therefore, paradoxically, the two dog and cat dissections that occurred *after* Yoshihito's death were probably my sister's doing. Inspired by Biwashima, her old bloodlust must have stirred, I guessed. I lamented her warped personality, how being raised overprotectively made her unable to endure things. That's a lie, though.
Her outing on the night of February 14th was probably also in search of prey. That's why she was carrying a knife and armed with a bat for her first outing in a long time.
"Actually, for reasons I can't disclose, I was searching for that elementary schooler."
"...Was she also witnessed at the scene where Yoshihito was murdered?"
"Ahaha," Biwashima laughed with only her voice, her facial muscles not twitching in the slightest.
Stubbornly refusing to admit she's the culprit, huh?
......What did Biwashima and my sister do on February 14th, and how did they meet?
Honestly, without forcibly prying open both their mouths, it's impossible to get beyond speculation. However, I think I've arrived at a reasonably correct answer.
Biwashima must have been witnessed at the murder scene by someone. Compared to her previous pattern of animal killings, the mutilation of Yoshihito's corpse—specifically the lower body—was incomplete. Doesn't that imply something happened that forced her to interrupt her work and leave the scene?

And I speculated that the witness was my sister. If it hadn't been, Biwashima should have already been reported. The only person who could possibly fit the criteria of witnessing a murder and *still* not reporting it—given she was running from the vicinity of the scene on Valentine's night, covered in blood, carrying a knife and a bat—is her. After all, she probably made off with Yoshihito's internal organs like a scavenger at a fire scene. Whether my sister returned to the body later, after escaping Biwashima and the others, to obtain them, or some other sequence of events—I have no way of knowing. Alternatively, Biwashima might have chased the witness, harmed them, and fled without being able to return to the scene. However, the only person murdered in town in February or March was Souda Yoshihito, and there are no missing persons reports. If even one such case emerged, the media would jump all over it.

And so, Biwashima, pretending to escort Ichimiya, had been scouring the city late at night, searching for the witness—my sister. That's what I figured.
The blood on my sister's clothes must have been Yoshihito's bodily fluids, splashed on her during her work. The work of slicing open Yoshihito's abdomen with a knife and dragging out her target, the small intestine. Opportunities to taste human flesh probably don't come around often. That's why my sister, despite never having killed a person, was in possession of human—likely Yoshihito's—small intestine.
"So, I cheerfully went up and spoke to her," Biwashima said. Liar. You were totally planning to kill her.
Or perhaps she was curious about why she hadn't been reported yet.
"Surprisingly, she stopped her work and answered me. And then she proposed a deal. I decided to play along with the elementary schooler's little game and accepted."
"Did she offer some condition in exchange for keeping quiet about your crime?"
"Senpai's Japanese seems to be encrypted; I can't understand it at all."
Seems like you can understand and hear Japanese just fine, given that you're replying.
"What that elementary schooler demanded was for me to explain, as much as possible, the details of the kidnapping incident that occurred in this town eight years ago."

The impact traveled from my eardrums to my semicircular canals. A persistent distortion, as if my right eye had shifted up to my forehead, assailed and dominated me.
"I don't really get it, but she said something about not having social connections or something, so she couldn't ask anyone else."
She's a genuine shut-in, after all. Her rightful place is under a tombstone. A dyed-in-the-wool recluse; her proper bed is six feet under.
"Eight years ago, I looked into the kidnapping case out of curiosity. Since I was just a kid, I couldn't get much info beyond a child's reach, but I already knew about the three victims who were rescued."
There, Biwashima looked up at me for the first time in a while.
Well, if she didn't know the victims, she wouldn't be calling me and Mayu "Senpai," would she?
"Putting aside why she'd want to know about that now, I like kids so much I end up liking the preschool teachers too. So I just told her what I'd found out about the case. She was breathing heavily, wanting to know the most details about the survivors."
"Hmm............"
"What do you call it, 'grudge talk'? I could really feel the 'I'm gonna kill you' vibe coming off her."
"Since you also killed Yoshihito, Biwashima, you could sense a kindred spirit, I suppose."
"Senpai, does any of this ring a bell?" She ignored me with Inazawa-level爽やかさ (freshness/nonchalance).
"Searching... Nothing relevant found up to the 'Ta' row yet."
Wanting to know about the survivors of the incident probably means it's related to her mother.
If she intends revenge, focusing on the living rather than the dead is the practical approach.
Because whether it's true belief or falsehood, getting a response is crucial.

So that's why she was stalking me, targeting my life as a survivor, trying to dig up information about my mother, swinging that bat around and trying so hard.
......Hm? There were three survivors, weren't there?
Wait, in that case—no, surely not—Mayu too?
She pointed a kitchen knife at me but ultimately stopped. But if that's the case, did she suspect me, and—
No, but the tip of the metal bat was pointed at Mayu.
That word, '邪魔' (hindrance/obstacle)... could it be that I misunderstood?
"When I told her two of the survivors were living together, she seemed really torn about something... Oh yeah, considering she also asked for the address, maybe she planned to wait until one of them went out and target the other one at home. Ah, speaking of which, Senpai, you're out today, aren't you?"
Matching Biwashima's lighthearted tone, something sharp pierced the space between my eyebrows.
I shuddered, unconsciously loosening my grip on Biwashima's hands.
And finally, the knockout blow.
"Today seems like a good opportunity, maybe she plans to kill Misono-senpai first?"

I genuinely felt the illusion that my head had twisted off, and accepting this fact, I spun around and leaped back.
I started running. Leaving Biwashima behind, I broke into a sprint. Breathing so hard and ragged I felt like I might suffocate from my own panting.
"Hey, Senpai! I didn't actually think you'd let me go!"
"Do your best to die!"
Like I give a damn about my classmate right now!

But still, report it, report it! Uwah, almost dropped my phone!
"Ah, Natsuki-san! No jokes right now! Biwashima Yagoto! She's at the community center now, near where Yoshihito died—yes, around there! She's the one who killed Yoshihito! She's still nearby so you might be able to catch her! Even if she runs, you can secure her quickly! Ah, please check the bloodstains on the shinai bag and investigate her room! Thanks!"
Hang up! Keep gripping the phone! Run!
"Kyaaaaaaaaaaaaaaaaah!"
Gotta run! Goootta ruuun!
It's not irrelevant at all! That time back then, was it reconnaissance for a perfect execution?! You damn sister!
Aaargh!
Lungs working overtime unpaid, eyeballs missing wages, muscles overloaded, dull ache in my right foot!
Fine, right foot, just die already! The pain is intoxicating!
You've been alive too much in this short time! Let it stay dead a little longer!

By the time I reached the apartment building, my knees were buckling, and my breathlessness had reached its limit, tipping into hyperventilation that felt like laughing. My runaway mental state had calmed down due to sheer exhaustion, or rather, I was half-dead, tormented by sweat and heat. Calming down, the possibility that Biwashima had tricked me seemed high. I had acted recklessly without confirmation. I'd lost my phone somewhere along the way too. Anyway, I took the elevator to the third floor and dragged my right foot towards Mayu's room, rushing as best I could in my current state.
"Uwah............"
The lock on Mayu's door was destroyed, the chain severed. Forced entry confirmed. Kicking the door open with the rebound, I rushed inside without taking off my shoes. If Mayu and my sister were here, it would be the bedroom.
"Mayu!" I yelled, clinging to the hope as I burst into the bedroom, and—
"... ..."
A scene unfolded that left me bewildered, unsure what to yell next. I choked back a cough. Sweat dripped down the bridge of my nose.

My sister by the window and Mayu near the bed were facing off.
My sister leaned forward, holding a dripping knife. Mayu stood glaring back, her right arm hanging limply, a spectacular tunnel of fresh blood and a small fountain erupting through her nightwear where she'd been stabbed. They were locked in a standoff.
The two girls pierced each other with gazes full of hostility, like predators or perhaps members of the same species filled with mutual loathing.
And I was the one who threw cold water on the situation.
"Ah, Mii-kun..."
Mayu turned to look at me, her voice inappropriately gentle.

Honestly, I didn't hesitate at all as I rushed to Mayu's side.
I moved in front of her, protectively holding her, supporting her. A slight sense of relief washed over me seeing no other knife wounds besides the one on her right arm, but still, a red light seeped behind my eyelids.
Mayu showed no sign of pain. She just slowly held up her right arm, smeared thick with blood, before my eyes.
That vivid wound was proof that Mayu had kept her promise.
The fact that my sister showed no knife wounds supported this.
Because she lacked the hesitation inherent to being human,
If Mayu had used a knife under equal conditions, killing her sister without getting hurt would have been far too easy.
And yet, Mayu's floor, the bedsheets, were stained with her own shed blood.
Therefore,
She looked like a kindergartener proudly showing off a craft project to their parents.
Mayu's expression was filled with pride and expectation.
"I... I kept my promise..."
"Yeah... Yeah."
Why use those words at a time like this?
"Move! Get out of the way!"
A scream erupted from behind me. As I turned, I reflexively stuck out my foot.
It happened to collide squarely with my sister's chest as she lunged, turning into a perfectly timed interception.
My sister's eyes widened in shock. The knife went flying through the air as she fell hard on her backside, sliding back towards the window again.
It was my first experience kicking my sister.
The sensation of the sole of my foot impacting bone lingered vividly. But I backed up a few steps, putting distance between us.
Coughing violently, my sister continued to glare, her eyes demonstrating raw hostility.
Her face—had Mayu punched her?—was swollen on the right side, the puffiness of her cheek starting to impede her eyeball's function.
Something present in this confrontation with her that wasn't there with Sugawara.
A tiny bit of guilt. A huge debt of gratitude towards her mother. A slight sense of unease.
The trembling of a coward.
"Get your misunderstandings straight already, dancing to the tune of flimsy rumors. Listen up, the one who killed your mother was me! I had her die so I could live, Mayu had nothing to do with it!"
"Liar!" she instantly shot back, her voice short.
Since the only weapon at hand was something soft like a pillow, I substituted with a lie, as is my style.
She pushed herself up using the window, staggering. Tears welled in her eyes.

Holding the silver blade out in front of her, my sister weakly lifted her chin.
Forcing back tears.
"Anii-chan wouldn't do something like that."
She spat out words that felt designed to tear my brain apart.
...Now, *now* she pulls that out?
But thanks to my interactions with Anzu-chan, that experience is already thoroughly worn out.
I know that being called that doesn't stir any deep emotion in me anymore.
And yet, what a perfectly awful way for us to use that word.
It would be effective here to recount a precious memory, but unfortunately, all we've ever shared are raw, unfiltered interactions.
"That's right, that's right, that's right, you! You're my brother, so why are you over there, protecting a stranger?! Are you crazy?! Yeah, you are! Your whole family is messed up! Always ganging up on me, bullying me! You never did anything for me, and Mom too! I hate Mom too, I hate her! I hate you too! You could have helped me just once! You're not my brother! You're a failure! Just die, die already!"
My sister pounded on the windowpane with her bare hands, screaming hysterically. Had the confusion completely permeated her? She was even denying her own mother, her only family, refusing to break her stance of frantic frenzy.
To be disowned as a brother just ten seconds after being called one.
Truly, why *am* I confronting my sister who holds a deadly weapon? Why can't I be by her side?
Because Mayu kept her promise?
Because you still only have a nosebleed? (Not true anymore.)
That might be part of it, but what's the deciding factor? I can't納得 (understand), 合点 (grasp), or 得心 (accept) it.
Just kidding.
"You're my brother, right?! Why won't you help me?! Kill her! The one who killed Mom! Hurry! Huuurrrry!!"
The spoiled brat stamped her feet, crying and wailing. Demanding it desperately. Inciting me.
Because I'm her brother. Because we're siblings, I should help.
Even if I were forced to, brandishing the principle of self-sacrifice her own mother held up, there's nothing I could do.
I can't become someone like your mother.

I'm living as a different kind of person than someone who wants to become human quickly.
...I do feel indebted. Enough to be traumatized, engraved in my soul.
But you and your mother, even if you share blood, even if, unscientifically, her soul and heart were passed down to you, you are different people.
Compassion is repaid to the one who gave it.
Unless the giver considers reciprocation towards others as sustenance for themselves. And besides, dead men tell no tales.
"What are you talking about? Mii-kun doesn't have a sister," Mayu interjected, having listened to the exchange, pointing out the contradiction that existed only for her.
"Mii-kun? Shut up, you psycho! Acting all innocent! Killing people and living like nothing happened! You're just a criminal everyone despises!"
She's been surprisingly accurate with her guesses for a while now.

Well, that is, how should I put it, very correct, and very wrong.
Mayu is indeed a murderer. She ended the lives of my parents, your parents, her own parents, with her own hands.
But if no one can prove it, if no one can recognize it as a crime, then for Mayu, such a thing exists nowhere, and she has no qualms living without blame or regret.
Her life has already deviated from the realm of forgiveness or being forgiven.
Therefore, a person who can't even cling to such values for dear life and live laughing—
"At the very least, don't include me in that 'everyone'."
Even in rejection, that was the best I could muster.
Something in my sister's face and heart twisted violently.
Mayu looked down at her sister with a cold gaze and snorted derisively, as if mocking her.
The blood dripping down Mayu's middle finger forced me to view an intense déjà vu.
An entire field of... corpses.
"The liar is saying something," Mayu murmured, dismissing her sister.
Her bright red palm stroked my cheek. A light, gentle sensation of blood. Maa-chan's small, blood-soaked hand.
"She's a liar, and so are you, Mii-kun. You just lied, didn't you?"
"Wha— Huh?"
Red confusion visited me, cutting through my thoughts.
Why would Mayu know that, about the presence or absence of memory—impossible.
"Mii-kun would never kill anyone."
"Eh? Ah..."
"So *she's* the bad one."
Mayu slipped out of my arms and charged at my sister. Walking briskly, straight towards the naked blade. With transcendent footsteps, she closed the distance in four steps until her abdomen touched my sister's knife. Then, faster than my sister could thrust, Mayu slammed her left fist into her cheek. The impact made my sister buckle at the knees, leaning to her left. But she recovered, sputtering foam, and lunged forward with the blade held in both hands.
Mayu flicked it away with the pad of her index finger.
The instant the knife tip touched and pierced her skin, her index finger knocked it aside, leaving behind a small amount of blood and flesh. In a situation where failure could have meant getting her throat hollowed out, she executed the move with utter ease.
The knife's direction forcibly changed, Mayu swept the stumbling sister's legs out from under her, sending her crashing to the floor. Twisting her arm, Mayu snatched the knife away. As promised, she didn't resort to the act of stabbing her to death.
Mayu glanced at me, then, as if struck by an idea, dropped the knife onto the floor.
"What—"
Mayu released her hold on her sister, stood up, thrust out her right palm, adjusted the angle, and held it low.
My sister, recovering her posture, picked up the weapon and lunged upwards at Mayu like a spring-loaded toy.
Mayu didn't even try to avoid the knife; she stopped it with the waiting palm of her right hand. A silver bud sprouted slightly above the center of the back of her hand, one that would never grow. At her utter lack of hesitation, my sister's cheek twitched almost imperceptibly. Mayu pulled her right hand back, wrenching the weapon free, then kicked her sister in the stomach, knocking her down. And then, she stomped. Again and again. On her neck, her solar plexus, her face. Her nose, her eyes, her tongue.
Because Mayu didn't have the decisive tool of a blade. That's why, she had to get so, so wounded, while—
My sister could only writhe in futile, childish defense, with no time even to escape into screams or coughs.
This was fundamentally different from the clumsy scuffling my sister had subjected me to.
Realizing *that*—by acknowledging *me* internally—Mayu finally cast off her confusion.
I rushed forward and tried to stop Mayu. I grabbed her left wrist from behind, making her turn.
Even as she looked back at me, Mayu kept stomping on her sister.
"Stop this, we need to get you to a hospital quickly."
"Not yet."
Mayu shook her head quickly. Her expression wasn't clouded, nor did it hold any pleasure.
It was cold, just like Sugawara's on that night.
She firmly pulled the blade from her right hand and, without wiping off the blood, tucked it into her pajamas this time.
"I have to make her die." ("Koitsu o shinjawasenai to.")

"Wha— Hey!" That's not even proper Japanese.
"So Mii-kun should just be quiet over there—"
Mayu shook me off, shoving me with her right hand. Caught off guard, I couldn't even brace myself and landed hard on my backside, hitting the wall awkwardly. Wincing at the spasms in my legs, I exhaled a lump of air and looked up at Mayu.
"It takes time to make someone die without tools, so wait a little," Mayu declared in the same casual tone one might use when asking someone to wait for dinner to be ready.
"And also," she added as a preface, showing me her right arm with the hole in it.
"My right hand ended up like this. So maybe I can't cook for Mii-kun anymore."
*I'm sorry,* she seemed to say.
Mayu smiled faintly, ethereally, even as she trampled her sister's face.
And then, "So," she continued.
"Even if I make her die, we can go to prison together, right?"
"Oh..." Hey, hey.
Could it be... that right hand was intentional?
As an indulgence, a way to get my permission to kill?
... No, that's wrong.
That can't be right.
"That's no good."
"Why?"
Just kidding.
I need to stand up, I need to end this.
I need to take Mayu to the hospital, I need to force myself to talk to my sister.
This isn't the time to be denying things.
My words even stop Mayu's foot in response. What am I even trying to say by doing all this?
I don't need to pretend to think about it; I understand perfectly well.
Because it's about myself, restructured into something simple enough to make me want to vomit.
What I have to accept.
Not something presumptuous like 'to be human'.
Something more primitive, more fundamental.
*It's fine like this.*
*It's okay even if it's like this.*

Even if I add nothing and subtract nothing, lose the aptitude to become an adult, lose the past where I was a child, am hollow and worthless and ambiguous, capable only of living vaguely,
I accept it.
That something existed in this room, something beyond lies or truth, something that was neither, even if it was artificial.
"Then,"
I don't want to break anymore.
I don't want anything else to be broken.