It actually goes a lot faster once the loooooooooooooooooooooooong character introduction is done
Anyway. It looks like even the games says that anything Battler doesnt see cannot be trusted, as even at the tea party he keeps saying that Kumasawa could have killed Kannon.
Which is a bit sad and is quite a dangerous can of worms to open because it lets me ignore any reveal or event or character information that Battler isnt present to see:
I see Shannon talking with Gohda while he reads the magazine, but in reality they're having a fight to the death using nun-chuks.
Or Krauss showing the gold bar to Natsuhi, proving the gold exists. The event becomes meaningless because I can just say - Battler did not see the gold bar there for the gold might not exist. And use that to support my theory.
Disregarding events that are a hindrance and yet using others as important evidance (Natsuhi's near-despair and most important parts of her frustrations are not witness by Battler, so she infact might actually be the happiest person on the island).
Anyway I will try some speculations preseving POVs as much as possible (though Kannon probably wasn't killed by glowing butterflies). Naturally I asume there are only 18 people otherwise there might as well be 118 and the whole thing is pointless.
Maria is not the cuplrit
9 year old kid! Even if she used a friggin' icepick-gun to pick off people one at a time, there is no way you can recharge and fire that thing fast enough to kill 3 people at once in the parlor, nor could she ever ever pull off the first twilight. Just the circle would take her the whole night.
Natsuhi's conversation with Kinzo:
Definettly happens. Even if POVs are not to be trusted, this conversation must have happened at an earlier time. Natsuhi fiercly defended the "Ushiromiya wing on her heart". Even if that was just wishfull thinking, if that conversation does not happen, then Natsuhi is friggin' schizophrenic and last I checked headaches are not a cause or a symptom of schizophrenia. And even if that's just a fron she puts up - "it's just a headache", as she tries to supress the voices saying "kill 'em all", there is no way Krauss wouldn't notice in all these years and most definetly neither he nor Kinzo would let her stay or get into the family in the first place.
Kinzo's disaspearance from the study and Eva's paper-trick:
Still a non-issue. Noone ever saw that paper being placed or removed. Even if Eva is not involved with the murders in anyway she could've simply tried it as a ploy to check if Natsuhi would slip up and reveal something. Basically creating a clue where there is none.
Also for someone who had a gun pointed in her face she remained quite calm, which also supports a theory that Natsuhi and Eva might've been allied at least at that point, as they are also the only ones to confirm that Kinzo had dissapeared from the study.
Battler's theory about "body-doubles" prepared for someone killed in the garden storehouse:
A worm-hole riddled with holes.
1. How would they get the body on the island without anyone noticing in the first place? Krauss's family; Kinzo; Servants might have the ability to do so, however neither Shannon nor Krauss get to benefit from it since their faces are half-seen. Which leaves only Gohda as a possible "switcher"
2. Those body-doubles would have to be dead for at the very least a day before the 1st twilight. Nanjo would be able to notice that much which instatly requiers to make him an accomplace.
3. This switch falls apart the second the police and forensics get involved.
4. My biggest gripe with this theory is that I can "revive" anyone I please and up to four people.
Using Kinzo to "revive" someone in the garden storehouse:
While on the subject of "body-doubles". If Kinzo is infact missing from the study when Natsuhi "talks" with him, someone in the storehouse could try fake their death using Kinzo, but...
1. Only Gohda and Rudolph can benefit from it - Krauss's face is seen.
2. Does Kinzo's figure even remotly resemble any other male on the island? Battler compares his own figure to a couple of people, but Kinzo doesnt get compared at all or described much physicly as far as I can remember.
3. Kinzo spent how many years in his study sitting and drinking? Not only is Kinzo much older than anyone else he also has to be very out of shape.
Even if the scene is filled with blood and everyone is chocked and disturbed, wouldn't close relatives notice a difference? Is the killer ready to even take such a chance when he's saying - "hey! look at this cool crime scene!"
Closed room and 2nd twilight:
This one is an incredible pain for me. In this situation I guess police would first assume suicide or murder+suicide?
However it is nearly impossible that someone would be able to pierce their own skull with an icepick. Unless they try to fall on it, which isnt the case here.
Also
Eva knows martial arts! She couldn't be overpowered that easily.
Some kind of poison gas would kill them, but they still need to be stabbed by the icepicks.
So removing silly "hidden passages" the killer has to be still in the room, pretty much hiding under the bed. Worth the insane risk just to try and "impress" everyone? not really. Even if possible, killer also has to make it to the boiler room in time to fight Kannon.
And even if I remove the POVs as true I instatly have to add Genji + Kanon + Kumasawa as accomplices since they all "see" the door chained from the inside and still unbroken. And even then by that point Kanon already should be a very reluctant participant if his love for Shannon holds any water.
Kanon is killed when everybody's position is known and a dead end for the other killings:
Once Kanon get's fataly wounded and Kinzo's body is found all "bodies" are accounted for. As in all 18 people alive or dead are accounted for and their positions are known.
During the time only one body is unaccoutned for and can be considered as a live person doing whatever they want - 3 people are killed: Eva, Hideyoshi and Kanon. However since the last body is found straight after attack on Kanon, that "body" could only be responsible for Eva's and Hideyoshi's death and even that is a strech. After which the body has to be burned, found and there is noone left to do the killings since there are only 18 people on the island.
Which means:
1. Kanon is killed by a "trap". However this is a dead end. All 18 people accounted for after this and noone is left to do any more killings.
2. Kumasawa kills Kanon. Once again a dead end since it's beyond unlikely she can kill both Nanjo and Genji at once in the parlor and noone is left to kill Natsuhi.
3. One of the nine dead people at the time is alive.
At least of the nine killed before Kanon has to be alive
Eva and Hideyoshi are dead for good. You don't have to be a doctor to see that an icepick to the skull is lethal. Which leaves seven people. Six of those rely on making Nanjo an accomplice. And all seven need another accomplice.
Natsuhi is one of the main culprits
Locking the storehouse with a new lock that only has a single key and taking said key secures her a "guilty as charged". Thus wether she is the main culprit or a close ally, all my theories revolve around her being involved in the murders.
Natsuhi has a very strong motive of "I wasted my life for what exactly?". And even if none of her POVs can be trusted, there's still the "I have schizophrenia - kill 'em all". She might actaully sevretly be a firm believer in the hidden gold, which would let her become the successor, though that doesn't make her need to kill everyone and vice-versa.
So in my opinion Natsuhi get's involved either after Krauss shows her the golden bar and last of her elusions are crushed. Or she believed in the gold/was plotting against him long before that. All it would change is wether she's the one to give Maria the letter.
After the 1st twilight Natsuhi is nearly always with Battler up untill her death, so another person is needed for killings from 2nd to 8th twilight. However because of the "there are only 18 people", there are only seven suspects for that second person and all of them
need Natsuhi's key.
If Nanjo is also involved and one of the people from storehouse was actually alive, then they need Natsuhi's key to get out. If Kinzo is the suspect, then he needs Natsuhi's key to get one of the bodies from the storehouse to burn them and make it seem like all the bodies are accounted for.
If it turns out Natsuhi's lock could be picked/broken without her key then f*** my life.
Kinzo being one of the main culprits requires one of the 6 people in the storehouse to have the 6-finger disease
Pretty sure it said the rate was 1 in 2000. 6/2000 is not that bad for a man betting against improbable odds to create miracles. And since 3 of them are his kids the chances are even higher.
Also if you cut one of the fingers in half would it be noticed on a burned body? Or if you cut off a finger from another body and sew it to make 6 fingers? (I guess the threads would burn and it'd fall off)
Closing comments on theories.
My main problem is that I'm unable to solve the 2nd twilight's closed room. So I either have to instatly invole three servants to "break" the room or have Natsuhi's accomplice hide under the bed in the room (most epic murderer ever). I also think that it would be all but impossible to involve Kinzo's "furniture" without the man himself (unless they all secretly despise him, but that's going waaay out there). I'm also not a big fan of my "play-dead" theory. And since involving Kinzo does not require involve Nanjo, my suspects are this:
A. [Natsuhi, Kinzo, Genji, Shannon, Kanon, Kumasawa]
B. [Natsuhi, Kinzo, Genji, Kanon, Kumasawa]
C. [Natsuhi, Kinzo]
D. [Natsuhi, Nanjo, Person "X" from storehouse]
In "D" case any of the 6 could have a hidden motive and be involved. Mostly "$$$". Even Shannon can have a secret agenda/persona, who goes to the mantion to kill people despite being confessed to. And was she confessed to in the first place?
And no matter who it is their actuall role doesn't change. Being a woman is preferred to mess with Maria in the parlor. Bonus points if it's Rosa. This is also my only theory where "Beatrice" from the garden and "Beatrice" from the parlor can be the same person.
Cases "B", "C" and "D" require for Natsuhi to plot murder in advance. In case "A" she
can join after the letter.
The events. "A"
Shannon gives Maria the umbrella and the letter pretending to be Beatrice by orders of Kinzo. Kumasawa confirms her alibi. Natsuhi can also take Shannon's place.
On 1st twilight Shannon's murder is an accident during the struggle.
Kanon does not participate and makes sure no one leaves the guesthouse.
Natsuhi "paints" her own door.
If Eva's paper was a bluff Natsuhi talks to Kinzo in the morning. Otherwise the talk takes place some time before 1st twilight.
Natsuhi and her escort move one of the six bodies from the storehouse to the incinerator.
Natsuhi knows where to find the gun thanks to Kinzo.
After hearing about Eva's paper clue, Kinzo is informed and someone always stays at the storehouse. Once Eva goes there in the evening she is shot with the icepick weapon, taken to her room, where Hideyoshi is also killed. They leave the letter.
Kanon finally has a chance to confront Kinzo about Shannon's death, rebels and is killed.
Natsuhi places the letter in the study along with the food. Servants could also do it.
Kinzo kills everyone in the parlor, sends Natsuhi a secret message in the letter and shoots her with a different gun (it was said there was more than one).
The events. "B". minor differances
Natsuhi takes Shannon's place.
On 1st twilight Shannon was not meant to be in the mansion.
The events. "C". minor differances
Kinzo has to hide under the bed and then rush to the boiler room to fight Kanon. Sounds even dumber when I write it again.
The events. "D".
Too many improbabilities untill I solve 2nd twilight.