Memories 48-54

[thinkoutsidethebox]

Memory 49: Raising the stakes. "Even without the detective proclamation, I will defeat you!" [EP6] Form of a wooden handle. Turn it in the air. 2/3 uses remaining.

"That's right. ......I have one thing to say before we begin this game."
"Oh, that detective proclamation thing. Do as you wish."
"No, I mean the opposite. ......I say we raise the stakes."
".........Raise...the stakes...?"
"What's this? Now that sounds interesting. What do you mean?"
"......It's simple. Battler got a shot off at us in the last game. So, if Erika does the same in this game, we're only even."
"Wasn't the last game a tie...?"
"We threw a game we should have won easily, right? If that isn't a loss, I don't know what is. Right, Erika...?"
"Y, yes, my master. If I hadn't failed so miserably, we would have won that game by default..."
"......Ooooh, I get it. So this time, you'll intentionally fight at a disadvantage by not making a detective proclamation...and win despite that...! You're scheming to not only wipe out your loss from the previous game, but to totally flip the score upside down, right?"
"Y, ......you intend to challenge the game Battler-san poured his heart and soul into with a foolish handicap like that...? That is not only presumptuous, it's quite rude...!"
"......Sure is. It sounds more like an excuse just in case they lose."
"True, you could also look at it that way. If they win, it's a great victory, but if they lose, Erika's side has a nice little excuse. Isn't that a bit unsporting?"
"Don't worry, this bet is balanced on both sides. ......If we win as a human without the detective proclamation this game, it will be impossible for Battler and the others to pick up the pieces of the Illusion of the Witch. ......But on the other hand, if Erika loses, that detective trash will be sent into the depths of oblivion along with the worst possible Fragment."
"............"
"......See? That's balanced, isn't it? An ultimate victory with a mere human, not a superman detective, destroying the Illusion of the Witch. ......She's putting her own destruction on the line to make that bet. I've gotten bored with these sluggish repeating games that you and the former Beato made. ......So we're raising the stakes and settling it all at once."
"......Well, that is true.

......If Battler makes it through・・・・・・・ this game, it will mean that Battler has 'won' Beato's game, and the game will end. ......In a sense, it's a showdown you can't escape, right...?"
"..................I see your position. ......Are you okay with that, Erika?"
".........Y, ......yes, of course. ......In order to regain my master's trust in me, which was lost by my previous defeat, ...I...I will risk even my own destruction..."
"Is that of your own will...?"
"............"
"............"
".........What's wrong, Erika? Answer him, okay...?"
"O, .........obviously. This is my own will. ......I certainly will not lose... ......Even without the detective proclamation, ...I...I will defeat you no matter what...!!"
".........Battler-san........."
"..................Sure, that's fine. If that's what you want, I'll accept that challenge."
"..................Th, thank you very much. I'll make sure you don't regret it."
"After all, when Battler played for the human side, he never had anything as convenient as the detective's authority. All he was allowed to do was use the blue truth and ask Beato to repeat what he said."
"Exactly. In a way, the last game was unfair. .........We failed to win despite that, which is why it was no different from a loss."
".................."
"Do what you want. If you feel like making a detective proclamation, do it whenever you like. ......I understand that you're holding it in reserve at the moment."
"You really think......I would use it......? Against an opponent like you......?"
"............"
"Then get started, you two. I'm already starting to get bored."
"......Leave it to me, my master...!! I will destroy the Illusion of the Witch for you without fail...!"

Memory 50: Guaranteeing alibis: discussing famous mystery novels with Nanjo; meeting Rosa; party with Nanjo and Gohda [EP5] Form of a single teabag! The little paper tab on it has a single word, relating to your memory, but likely frustratingly unhelpful.

She describes this in the trial but it's mostly offscreen! She's with Nanjo in the book archive for the hours she's left open for the murder to happen, she runs into Rosa returning to the guest room, and then she's up late talking with Nanjo and Gohda in the downstairs of the guesthouse where she can guarantee that no one came in or out without her seeing.

Memory 51: Drinking with Kumasawa; the evil spirits of Akujikishima and Beatrice. [EP6] Form of a small penguin stuffed animal. Squeeze it for your memory.

"Hohoho, sorry to keep you waiting. I was just in the bath... ......Oh, where is everyone?"
"......You just missed them. They went up to the second floor. I'm the one who called you here. ......I've heard that you know a lot about the story of Akujikishima and the story of the witch of the forest."
"Yes, well. Hohoho. It is a trivial story, but..."
"I don't mind in the slightest if it's trivial. Would you like a drink to follow your bath? ......Even I like to be helpful every now and then."

Erika stood up, opened the refrigerator behind the counter, and put ice into the ice pail......

[...]

"But then, one night, purple lightning smashed the shrine. Those of the surrounding islands called it an evil omen. Oooh, now that I think of it, that must have been a prelude to Beatrice-sama's resurrection."
Kumasawa had the rest of the night off.

So, she had let Erika talk her into drinking a bit, and was chatting about the legend of Akujikishima and Beatrice in a happy, tipsy mood.
Erika would nod from time to time, but she listened very closely.

She wasn't actually taking notes, but she was gathering the information on the whiteboard inside her head.

......Then, she frowned as though noticing something out of place and held up her hand.
"Wait a second."
"Yes?"
"......That shrine was built by a traveling mountaineering ascetic to seal up the evil spirits of Akujikishima. Isn't that right?"
"Yes, that is correct. It was one who possessed a vast supernatural power, and who placed that power within the mirro-"
"And placed it within the shrine as a sacred mirror to seal the evil spirits. ......Something feels off about that. ......Why would a shrine to seal the evil spirits of Akujikishima also seal Beatrice?"
"W, ......well... That's, uh, because the power of the sacred mirror..."
"......I see. So it's this really convenient sacred mirror that works on both evil spirits from the East and witches from the West. ......Got it. I'm still not satisfied, but I'll back off there for now. What I don't understand is why Beatrice can't stand spiderwebs."
According to the legend, the evil spirits of Akujikishima despised spiderwebs, so they were apparently used as wards against evil in the surrounding islands.
Actually, spiders are a useful bug.
There was nothing strange about the fact that the farmers of the islands had treasured them.

It's very possible that they were then tied to the story of evil spirits and became known as charms against evil, leading to a tradition of people treating this useful bug with care through the generations...
"But that's just the legend of Akujikishima. The origins for the legend of the witch Beatrice came after Ushiromiya Kinzo moved to this island, when rumors sprouted about the mysterious legend of the gold and his mistress who gave it to him as a witch."
"In other words, the evil spirits of Akujikishima and the Golden Witch Beatrice are completely different things. And yet, their setup is treated in exactly the same way."
"W, ......well now......"
The evil spirits of Akujikishima couldn't stand spiderwebs. So neither could Beatrice.
That sort of reasoning has been applied all over the place.

......When it was pointed out that this was strange, Kumasawa was lost for an answer...
"The doorknob to Kinzo-san's study has a scorpion magic circle drawn on it, which represents a charm against magic in western sorcery. That's why the western witch Beatrice can't touch it. ......I can understand that part."
"But there's no reason for Beatrice to dislike spiderwebs. I don't remember spiderwebs ever being included among things witches can't stand. On the contrary, wouldn't spiders be the friends and minions of a witch?"
"W, ......well......"
"In my opinion, ......those two legends about the evil spirits of Akujikishima and the witch Beatrice...have been mixed together a little. In fact, maybe they've been fully joined together as one."
"......The legend of Akujikishima is a fairy tale created by fishermen fearful of reefs in the Rokkenjima area. However, there was no visual image to go along with those evil spirits. Were they people, or monsters, or ghosts without legs? There's no mental picture of them. People are bad at imagining things without visuals. ......And that's when the legend of the witch called Beatrice came in."
"A witch is a lot easier to picture than evil spirits. And on top of that, Kinzo-san had a portrait of Beatrice drawn and displayed. In other words, the lack of a visual image, which was the one weak point in the legend of Akujikishima, was finally completed. At some point since then, perhaps the two legends have been mixed together."
"W, well, I wonder...... ...H, ......hohoho... It is a bit confusing for an old lady such as myself..."
Kumasawa laughed to smooth it over, wiping away a cold sweat...

She might have seemed confused, but she actually did understand what Erika was saying.
......In truth, she had been vaguely aware of how the legend of Akujikishima, which had been around before Ushiromiya Kinzo had come to Rokkenjima, and the legend of the Golden Witch, the story of the woman who had given Kinzo a vast quantity of gold, ......had both transformed.
She didn't want to acknowledge it, ......but she knew.

The 'setting' where Beatrice hated the spirit mirror and spiderwebs.

This had been based on the ancient legend of Akujikishima.
The 'evil spirits' part of that legend had just been replaced by the witch of the portrait......
"......So, if there really was someone claiming to be the Golden Witch Beatrice, I'd really like to ask her whether she actually does hate spiderwebs or not. ......What happens when she touches them?"
"I, it is said that witches and their minions.........receive burns when they touch spiderwebs......so that is probably what would happen, I guess..."
"Hmph, that's not bad. A splendid witch trial. ......If the spiderweb touches her and she gets burned, then she's an evil spirit, not a witch. ......And if nothing happens, then it proves she's just a human."
"In other words, .........whether she's burned or not, it will prove that the Golden Witch doesn't exist. ......The legend of the witch is nothing more than the legend of Akujikishima re-boiled with a new face on it."
".........W, ......well........."
"Simply by the existence of the legend itself, reasoning of this level is possible for Furudo Erika. What do you think, everyone......?"
Though only the two of them were in the lounge, Erika faced in the direction an invisible audience would have been if there was one, and shrugged...

Memory 52: Quiz party with Maria's puzzle book. [EP6] Form of tin statues of horses that can fit in your palm. Wind the base once, and it will spin around for one memory. 3/4 uses remaining.

"If you're so confident in your reasoning abilities, you must be really good at quizzes and puzzles, right?"
"Oh, right. Maria, didn't you bring a quiz book or something?"
"Uu-! Brought it!!"
Picking up that Erika's arrogant statement had made the atmosphere a little more tense, George smoothly changed the subject.
By now, it was more than clear that she wasn't the cute guest she had appeared to be.

Maria pulled a book out of her bag that had quizzes and puzzles written on it and started reading them to everyone.
It might have looked as though it would become a peaceful quiz party, ......but of course, that isn't what happened.
In credit to all her big talking, Erika managed an impressive ratio of correct and immediate answers...
Erika took complete control. ......Her bragging began to escalate more and more.

George slightly regretted the choice he had made when changing the subject.
"106 matches. No need to even write a tournament chart for it."

The question, how many matches would you need for a tournament with 107 teams, was answered instantly by Erika.
"This is less of a puzzle than it is a test of knowledge. There's a formula which shows that the number of matches is always the number of teams minus one. ......Well, if you just look at the examples showing three matches for four teams and seven matches for eight teams, it should be easy to figure out the pattern."
"Uu-! Erika, that's awesome!"
"Erika onee-chan, right?! Say it."
"Uu-, Erika onee-chan, that's awesome."
"Really impressive. .........So, you don't call yourself a detective for nothing."
"I couldn't very well act the part of the detective if I was incapable of handling puzzles of this sort."
"Incredible. I'm sure you'll be able to become a real detective in the future."
"Well, I'm pretty sure I already am one."
The cousins all thought about the answers to the questions, but Erika always answered first.

Rosa thought that it was a bit rude for Erika to say the answers out loud while people were thinking, instead of keeping them to herself, but since Erika was a guest, Rosa decided against mentioning it.
......In truth, Erika was perfectly aware of this when she answered the questions instantly.

Each time, she would grin broadly, as though saying 'you all still haven't solved such an easy problem?'...
"......Since you're a great detective, you don't really need to take this so seriously, right?"
"Good point. Even though these are just childish questions, I've been taking them a bit too seriously. ......I'll take more care, so let's hear the next question please."
"Alright, I won't lose this time. Maria, next question please!"
"Umm, ......you have one large piece of cheese. A single slice with a knife can split it into two parts. So, what is the lowest number of slices you can make to cut it into eight parts? Uu-!"
"Oh, I know this one. So I guess I'll stay quiet this time."

George, acting like the adult he was, set up a mood that would prevent people from answering right away even if they knew the answer, in effect sending a warning to Erika.
It seemed that Erika understood, and she averted her gaze, snorting derisively.
"......To make eight pieces, four slices would be enough, right?"
"That's dumb. It would hardly be a puzzle if that was the answer."
"Hahaha. That's right. These are usually set up so that a smaller number than you'd expect is the answer. But still, how exactly could it be done?"
"......Oh, got it, got it. You can only do this because it's cheese."
"True. If you tried to do it with a birthday cake, there'd be a huge fight."
"Wahahaha! That's right. You might be able to do this with cheese, but you'd never cut a cake like this."
"Huh? Huh? All of you know the answer?! Dammit, am I the only one who doesn't?!"
"Oh, I've got it! I see, so you have to think three-dimensionally."
"Wait, even Jessica?! I don't get it! What should I dooooooo?!"
"Kihihihihihi, I know the answer. It's written right here. Kihihihihi."
"You didn't know the answer until you looked, right? *giggle*, get it? Battler-kun?"
"I see, I understand it as well. This is something you can do because it is cheese."
"Gyah?! Even Doctor Nanjo gets it?! Could it be? Am I the only one who doesn't get it?!"
"......If we tried cooking your brain a bit, it'd probably become as flexible as cheese. *giggle*giggle*......"
"It isn't something like 'use zero slices with the knife and break it apart with your hands', right?"
"Of course not. It's impossible to cut this cheese with anything other than a knife."
"Think of the cheese in three dimensions. If that's hard, it might help to draw a picture on a paper napkin."
"S, so, we have one large piece of cheese, right...? Then we use a knife to make eight pieces...... ......Can the knife only cut in a straight line?"
"Yes, that's right. The knife only cuts in straight lines. ......Oh, but here's a hint. You can only cut in a straight line, but you're free to cut it wherever you want."
"Try thinking of various ways to stick the knife in."
"You should probably try to think out of the box a bit. Show us what you've got, Battler-kun."
You have a large piece of cheese.

How many times must you cut it with a knife to make eight pieces?
It's obvious that you could do it in four cuts.

Can it be done in even fewer cuts than that?

The hints said that it was something that could be done because it was cheese.

If it was a birthday cake, you really wouldn't be allowed to do this.
".........Cheese. ...Cheese. ......Something you can do because it's cheese? ......Oh, ...oooooooooooohh!! I've got it, I've got it!! I was totally tricked! This isn't something you can think up with a stiff head...!"
"Seems like you've finally hit on it. Hopefully it is the right answer."
"It's impossible to cut the cheese with anything except the knife, right? The knife can only cut in a straight line, right? There aren't any other rules, right? Right?!"
"Uu-. Not really."
"Alright, then that's got to be it! Wheeew, that was a tough one...it's almost like a riddle!"
"Hahahaha, it's just that you won't get anywhere if you always cut down from the top. You make two cuts from the top to get four pieces. If you keep it like that and cut across the side, splitting it into an upper half and a lower half, you get four times two equals eight pieces!"
"It's an answer you can't reach unless you think three-dimensionally. In other words, the correct answer is three."
"......Huh? Really? I......thought the correct answer was one."
"Wahahahaha! What kind of magic did you use?! There's no way in the world you could manage it with one."
"*giggle*. This isn't a riddle, it's just a normal math problem."
".........Huh? Oh, ......really...? Nnnnn, I thought of the three-cut method right away, ......but I figured that was too easy, so I guess I tried to twist it too far......"
"......Battler's answer is smaller than the one in the book. Is Battler right?"
"Yes, he is. .........Battler-san is right. The right answer is one slice."
Battler was happy that someone had confirmed his answer. ......However, at some point, Erika's face had lost its cheeriness.
".........To think that a human other than myself would answer one...and that it'd be you, of all people."
"Your answer was one too, Erika? ......I guess you were also thinking out of the box."
"It would be truly foolish to arbitrarily decide the shape just because you heard it was a piece of cheese."
"That's impossible. Onii-chan got it wrong, didn't he? How could you cut it into eight pieces with less than three slices?"
"How foolish, child of man. *giggle*giggle*...... It says to cut it into eight pieces, but nowhere does it say that they have to be of equal size..."
"It's still impossible. Do you cut it with something other than a knife?"
"The rules say that only the knife can cut it, and that the knife can only cut in a straight line. However, to turn it around, the rules do not say anything besides that...... In fact, the shape of the cheese is never specified."
"I get it... When you all heard 'a large piece of cheese', you thought of a flat cylinder, like Camembert. ......I was thinking about sliced cheese, like the kind you might put on your toast for breakfast. ......After all, I don't usually have anything to do with full blocks of cheese that you'd cut with a knife."
"......The shape of the cheese isn't specified in the rules. A mistake by the ones who made the book. I imagine that there's a picture of a flat cylinder of cheese there in Maria-san's book."
"Uu-. There is. Right here."
As Erika had guessed, the book Maria held had an illustration of a piece of cheese just as Erika had described it.

......With cheese of this shape, three slices really would be the correct answer.
You cut it in a + pattern from the top to make four pieces.
Then cut it from the side to double that and make eight pieces.

However, since this illustration hadn't been shown, the interpretation of the cheese had been left to the answerer.
"......That is right. When the problem was stated, it never said anything about what the cheese's shape was or how flexible it was."
"Exactly. It seems that Battler-san was the more flexible one when it comes to both brains and cheese."
"I, ......I don't get it. How does making it sliced cheese let you cut it into eight parts with a single knife slice?"
"Why not try it with that paper napkin. Pretend it's sliced cheese."
"......It's like this. You fold it accordion-style. ......How many times do you need to fold it to make eight sections...?"
"Six times."
To fold it accordion-style, you alternate between upward and downward folds.
Once you've done this six times, it looks like the side of an accordion.

"With normal cheese, it'd break if you tried to fold it like this, ......but the rules say that this cheese can't break unless you use a knife, right...?"
"Yes, no problems there. After all, this is magic cheese that can only be cut by the knife."
"After folding it, ......if you start at the top and make a cut right down the middle..."
"......Y, ......you're right. ...There are eight parts."
"W, wait a second. The parts aren't all equal this way, right...?!"

"......All the questioner said was to cut it into eight pieces. They didn't say anything about them being equal. ......Well, if you change the way you fold it, it is possible to make them all equal sizes, but I wouldn't want to confuse you stiff-headed people with the explanation. Eheheheheheheheheheh......"
"Oh, ......ooooooohhh............"

For a while, everyone was stunned......
Battler had reached a far better answer than three by thinking of the problem as a riddle.
Erika had already known both answers and had even spotted a mistake made by the book.

......The others could do nothing but stare at those two in surprise.
"I, ......incredible. ...So we were the stiff-headed ones...?"
"What...a failure."
"We were thinking in three dimensions, ......but it looks like Battler-kun and Erika-chan were thinking in one dimension higher."
"......It seems the game with the witch has toughened you up quite a lot. ......Puzzles without specified rules--in other words, all things not covered by the red truth--are left to the observer's interpretation. ......It's the most basic of methods for constructing gaps in the witch's closed rooms."
"What are you talking about...? Is that a quote from some novel...?"
"...............Well, let's call it that for now, shall we? Anyways, I guess this means that everyone's brains are as stiff as rock-hard cheese. *giggle*giggle*giggle*...!"
Without any signs of restraint, Erika looked at everyone and laughed sarcastically...

Memory 53: Sealing up the survivors; appearance of the letter; "Actually, I had already sealed one place. I apologize for taking so long to report this to you." [EP6] Form of a memory-sharing stones. You and another person must each hold part of the stone to see the memory. Both characters will see it, but it will be more vivid for the person whose memory it is.

When Erika dropped her gaze to open her umbrella, ......she noticed something lying at her feet.
ERIKA: ............!
DLANOR: It's.........one of the usual LETTERS.
It was one of those letters sent by the witch......with the seal of the One-Winged Eagle on it.
It had been wedged under the outside mat in front of the entrance......as though someone had predicted that Erika would eventually leave for the mansion by this way.

It was in the shadows of the large eaves, so it had avoided the rain entirely.
ERIKA: ......So, it's here already. ......Almost as though it was waiting for me.

She bent over and picked it up. ......She then tore it open recklessly and pulled the letter inside out of it.

A message had been written in neat letters...
ERIKA: Welcome, Furudo Erika-sama......it says. ......Oh, so it's calling me by name? They totally saw this coming.
DLANOR: What does it SAY......?
ERIKA: It's an advance notice for a crime. No, I should say it's a report after the fact. ......Apparently, they have taken Ushiromiya Battler's corpse. It says something like 'please try looking for it'.
DLANOR: ......So this isn't the 'tear apart the two who are close' of the second TWILIGHT?
ERIKA: Well, disappearing corpses happened a few times in Beato's games too. There's nothing really new about this.

Erika shrugged and scorned the letter.
However, ......this letter was a real attack.
All of the survivors were sealed in the rooms on the second floor.

And, after Krauss and the others had gone around checking doors and windows, Erika had personally made sure that there was nothing at this spot.
So, it was an attack saying 'someone who shouldn't be here placed the letter', and that the someone was a witch.

......That was also an attack that the old Beato had often used.
ERIKA: Haah, sheesh. If the way you show it is the same, please tell me that the actual trick isn't the same too. ......Dlanor. Please call Battler here.
DLANOR: UNDERSTOOD. ......Lord BATTLER, we wish to take our turn...!
BATTLER: Got it. Let's have it.
ERIKA: My apologies. Actually, I don't have a new move to announce.
BATTLER(?): .........?
ERIKA: Actually, ......sorry. There's something I need to apologize for.
Apologize......?

Battler and Beato's eyes went wide.
However, though Erika said that she wanted to apologize, she had a confident look on her face, as though even that apology would be a new move.

......So, Battler glared at her dubiously, without letting his guard down.
ERIKA: It's about those retroactive seals. ......Actually, I had already sealed one place. I apologize for taking so long to report this to you.
BATTLER: ......You already sealed something? In other words, you've already used up all three rooms' worth?
ERIKA: Yes. I promised that I'd report on it right away, but I completely forgot until just now. You have my sincere apologies.
BATTLER: You don't look like someone who's sincerely apologizing... ...Well, that's fine. I'm the one who gave you that privilege. ......So? Where did you seal?
ERIKA: Dlanor.
DLANOR: Allow me to REPORT. ......Battler's guest room was sealed at the time of Lady Erika's inspection of the CORPSE.
BEATO: ............!

Beato tried not to let it show on her face, but her eyebrows twitched visibly and her gaze flicked over to Battler.
ERIKA: Normally, I would have liked to seal all of the closed rooms, but I didn't have enough duct tape. ......Out of respect for the Game Master, I sealed only the room with Battler-san's corpse.
BATTLER: ......So you were kind enough to close the lid on my coffin.
ERIKA: I remembered a short while ago and was planning to tell you when we reached the mansion and investigated the guest room with your corpse in it. ......However, when this letter appeared, I figured I should report it right away.
BEATO: Wh, why did you think that...?
ERIKA: Well, ......after all, Battler-san has been playing this game not knowing that his corpse was sealed in the guest room. ......Because of that, ......I thought, possibly......that it might change things regarding the appearance of this letter.
DLANOR: .........The cousins' room and the next room over are currently SEALED. Sorry for the late report, but the guest room with your corpse in it is also SEALED. And, there are 17 people on the island excluding Lady Erika. The existence of an 18th person has already been denied in a previous GAME.
ERIKA: In that case, ......the person who could have placed the letter......and erased your corpse.........I thought, maybe......heheheheheheheheheh... I thought maybe things might be different......
Erika laughed crudely while staring into Battler's eyes to see if he was panicked or disturbed...
BEATO: ............Battler-san......
BATTLER: ..................Stay calm. Erika has just made her report a bit late. There's nothing to be nervous about.
Erika had suspected it since the beginning.

It was possible that Battler actually hadn't been killed and was still alive.
And, if he was alive, ......then the letter that had suddenly appeared was easy to explain, ......even though all of the 'survivors' were sealed up.
Judging by Beato's faint agitation, ..........maybe......Erika's guess had been right on the mark.
Battler had played dead and somehow misled Erika's examination.
And then, when everyone had holed up in the guesthouse, he had snuck out of the guest room.
......Then, he had placed a letter, which was about how his own corpse had disappeared, in the entrance to the lobby...and hid himself......
If this was the truth, then the seals that had been placed on Battler's guest room at the time of Erika's examination...were now very significant.
In other words, if they had used this trick, then Battler would have 'broken the seals' when he left his guest room.
The trick would not be workable 'without breaking the seals'.
Since the survivors were all sealed in the guesthouse, then if the seals on the guest room were broken, it meant acknowledging that at least one of the victims was actually alive.

If Battler had known about the seals earlier, it was likely that he would have advanced the game in a very different way to avoid this.
In other words, it was very likely that an announcement about the seals would have had a large effect on the rest of Battler's game.
Erika was saying: 'if Battler, playing the part of the corpse, didn't want to break the seals and remained inside the guest room, the plot would not have included this letter'...

......If Battler was actually alive and had placed the letter there, then, now that Erika's seals had come into play, ......there was a chance that he would find a contradiction in his trick somewhere down the line.

That sort of contradiction is called a logic error.

[blah blah a bunch of super-meta exposition on what a logic error means]

ERIKA: This still isn't quite a logic error. And though we sealed the room retroactively, we are at fault for the lateness in reporting it. So, I have no problem with letting Battler-san retroactively rewrite the plot concerning this letter.
BEATO: ......Retroactively rewrite the plot...?
BATTLER: Hmph, I see. ......If 'I' placed the letter there, then that would be impossible as soon as 'I' was sealed in that closed room. In which case, this letter shouldn't have appeared here.
ERIKA: Correct. So, I thought you should have the chance to revise this small inconsistency.
DLANOR: ......We have discovered this letter HERE. ......We are saying that we do not mind if you want to undo that, or if you want to use a revised SCENARIO.
ERIKA: Just by the existence of the letter and duct tape, ......this sort of move is possible for Furudo Erika. ............What do you think, everyone...?
.........Damn, what a dirty move......
Well, ......what else should I expect from Erika...?

Memory 54: Trial: Start of the assembly, checking alibis [EP5] form of a sticky candy wrapper. Lick it to view your memory. 3/3 uses remaining.

I'M NOT PUTTING THIS ONE HERE IT'S THE DAMN TRIAL. Use your imagination. There's nothing emotionally impacting here, just setup for a puzzle she already knows how concludes.