I have a theory I'd like to share.
It was done after a lot of speculation, followed by looking up specific events. I did a lot of re-reading of this story, and holy hell. The bricks.
Fuku is the killer. She is guilty, but does not know it, simply because there are two flavors of Fuku: The grumpy, antisocial, cranky shotacon we all know and love, and The Bitch Inside Her Head.
...Let me backtrack a bit.
Fuku was an ordinary girl, once. But she had some kind of condition that could be activated in a certain way. (I think only a handful of people knew about this, the silver and golden haired people in that dream she had being among the few, if not the only ones, who did.) And one day, someone did. She recounts the story to Kazuma as it being a friend that called her, but as we shall see --and have seen, if you've been paying attention to the plot-- Fuku's memory is not always reliable. Most likely, it was tampered with.
Fuku's condition was activated, causing her to go fucking nuts, and murder her entire family. Very little of her family's slaying has been discussed, but it was noted once, if not twice, that she had blood spattered on her shoes from then... which means she was AT the scene of the murders AS they were occurring --possibly as a bystander, but given the evidence (and who would just leave a witness like that), most likely as the perpetrator.
When she came to her senses, she freaked the fuck out, and went into massive denial, unable to acknowledge that she'd killed her family. And so, in order to cope, she became a cold, unfeeling, unhappy person... and the old Fuku, the one who killed her family, the one who freely expressed emotion and smiles and humor and whatnot, became Headbitch.
She ran away from home, still holding onto the cell phone on which she had recieved the call. Somewhere along the line, somehow, SOMEONE called her phone: her new employer. It's not hard to guess how he managed to do so; he had called her in the first place. He began to have her delivering packages, then.
However, note something about the nature of her packages, or rather, the deliveries: The two people who received them (An unknown person in >>15071
, and Aki Hieda in >>17739
) -- do not appear to have been expecting them, which means that these people are being chosen intentionally by her boss. This strikes me as damnably suspicious.
And second, go look up the ASCII values of the phone number used by Fuku's boss.
Somehow, however, Fuku contracted her disease, the well-known-by-now Surprise AIDS. Its onset is marked by quickly spreading bodily paralysis. I believe that somehow, the packages are connected to her disease. She was noted as feeling good and healthy after delivering the letter to Aki, and he ended up DEAD. However, she also hadn't felt very good at all since entering Gensokyo. Surprise of surprises, she also hadn't delivered anything since then.
Now, remember how the news reports, back in the Outside world, contained mention of other people catching Surprise AIDS? How much do you want to bet that those people happened to receive unexpected packages from a scraggly looking girl? It's a long shot, but a very possible one. And besides, look at her name: "Hidden Killer"?
I've said this before, but that name strikes me as an awful good metaphor for a mysterious and lethal disease with no apparent cause.
YAF's also said that it's a metaphor for Fuku herself.
Somehow, Fuku was responsible for those, just as she was responsible for Aki's death. How?
It's in the numbers.
She is given a sequence of numbers when she checks her phone. She is given a sequence of numbers by Aki, who read them aloud to her.
As Aki was looking at the envelope, Fuku became more and more agitated, nervous, and impatient, wanting him to open the envelope already, almost like a junkie waiting for a fix. This may have been her condition making itself known subconsciously, sensing activation at hand. Then he opened it, and read her the numbers.
And what happened after that? A timeskip. A large and ominous timeskip, made more suspicious by the wording afterwards: >>17795 >In the end, it all went as usual. You 'wrote' the number down, thanked him and left. Yeah, just like always. Nothing special about this one.
And those quotes around wrote seem kind of weird as well.
Let's skip ahead to Aki's autopsy report, read aloud by Kain: >"Ah, there we go. Expert appraisement signalized presence of foreign body in the wound, intensified activity of leucocytes in stomach and oral cavity areas... Presence of foreign saliva in oral cavity area...
1) YAF clarified "body" to refer to "some tissue and/or excretion."
2) Leucocytes = white blood cells. You know. Those things that help fight off diseases.
I don't know what the fuck Fuku did to him, but it sounds... really fucking weird. The closest I can guess is that she did something to stimulate an abnormally rapid growth of white blood cells, then fucking ate them out of him, or something really bizarre like that. If you have a better guess, I'm all ears.
Whatever the case, Fuku harvested white blood cells from Aki, ingesting them somehow, and left. Magically,
she feels better afterwards, having picked up her booster shot.
So, back to to her interrogation by Kain. Now, contrary to what I thought was a frighteningly sound idea in >>18997
, he isn't evil. He's just pissed
. He's most likely a nice guy, usually, but even Mr. Delicious became an asshole in the second arc of Higurashi, when he was damned certain that Keiichi had killed someone. Kain's got something even better than just cop instincts: he's got the fucking history powers. Did anyone notice what he was doing? >>18837 >"Eternity is relentless, Fukuzai Toorima." wait, how did he-- "Oh, don't look at me like that." you could swear he's covered his mouth just to hide that creepy smirk "I told you, I can already read your arrival. Your name is not a problem for me to see, Fukuzai... Or should I say... No, perhaps I shouldn't. >>18871 >"I'm afraid you misunderstood something." his sudden interuption catches you off-guard. He wasn't supposed to cut in yet! "Don't let my previous... lack of solemnity mislead you. I was merely distracted with reading your undoubtedly entertaining history." Reading history? But all he was doing was staring in your eyes with a creepy smile!
he's certain Fuku killed Aki. Bitch In The Head woke up when the numbers were read to her by Aki, and she took over, doing... something... to kill him.
And Kain is watching Fuku's history, watching "her" do that. He knows what Fuku's done that not even Fuku knows about. Hell, he even knew her real name.
One last thing. Sleep is Fuku's weak time. It seems rather likely that Headbitch is walking around in Fuku's body when Fuku is not sleeping well. Perhaps she isn't able to do that when Fuku gets good sleep, and feels relaxed and content? After all, when she sleeps badly, she progresses further towards Surprise AIDS.
So what do we do about all this?
Well, our package delivery is not as innocuous as it seems. It keeps Fuku alive, but kills other people. I'm not too fond of that. And moreover, Kain currently possesses the envelope that Fuku was NOT to let out of her hands at any cost. I'm torn as to whether or not we should recover it.
On the other hand, the next
recipient was Kazuma. And I'm half-tempted to let this next murder go through, just to see the "What the fuck?!"
Headbitch moment experiences when Kazuma is up and about again the next day, and her years of concealed murderan gaems are revealed to Fuku herself.
Of course, going to Moriya might not be bad. There's two or three shota there for Fuku to get her perverted hands on (The autumn brothers, and... whoever Suwako is, now. Maybe.), and maybe the help of a god or another priest could go a whole long way towards curing her condition, or removing the false memories Headbitch has been using.
And on an unrelated note, CoMN Wriggle is confirmed to be very trappy.