(Kiyohime's Room)

"Well," Kiyohime huffed, "I'm not sure why my appearance of all things mystifies you. While I do indeed have (Shapeshifting), I was summoned this tall and all. But, really, it just goes to further show that the humans agree with me."

"Humor me a bit... I don't get how going crazy over lies and looking older leads to humanity agreeing with you about Anchin," Sasaku said simply. "Obviously for the Rulers that first is due to (Madness Enhancement) which I guess means you didn't explain your angle of it to them either. Or they just didn't get it."

"Martha's all like 'I've tamed bigger dragons, alright?!' and Georgios is like 'I've given my word to not let you harm Chaldea.' And Jeanne is, uh, well she's different, I guess." Though she started off grumbling, the Berserker trailed off thoughtfully at the end. "But of course there's good explanations."

"I'm listening."

"It's about people telling lies, right?" she started off simply.

"That's what all signs point to, yeah."

"And it's not like (Innocent Monster) or the like, so that means he actually did break his promise, right?"

"Huh. Wouldn't IM show up on Anchin's Spirit Origin, rather than yours?"

"Look, Jeanne already tried asking me, 'Isn't it more like people with commitment issues rather than liars?' but that's definitely not who I am now, is it?!" Just remembering that particular exchange seemed to have fired her up somewhat.

"Er, I guess I see your point. What about the second bit?"

"When Gudako passed you the records on me, you immediately said I was twelve. Why?"

The Ruler took a moment to pull up her memories of that moment. "You didn't look middle-aged, so that was the most likely set of possibilities. You didn't behave like I was wrong?"

"Wrong or not, I don't know. And you and everyone else doesn't know either."

"Makes sense. But you do look as old as, say, Sakura when I last saw her," Sasaku raised an eyebrow, still not quite making the connection.

"Er, the former head of Matou? Didn't she basically get married around that time?"

"She did? I didn't get a full timeline of what happened after I, you know, died. Ah."

"You see it now? I'm like this because it's what people of this age expect from someone who was still young and about to get married."

"That... that-" The other Servant looked at her suspiciously, sensing that her space was about to be invaded. Right then, though, someone knocked on the door from outside. Or rather, it was a doorbell that sounded like a knock.

"What? Aw, we're out of time?" Kiyohime seemed mildly put out as the door opened to show Georgios with Gudako next to him. But she didn't move away either.

"Please tell me you weren't about to assault her," the Master frowned. "I'm serious, it seems like you need to be watched any time you aren't just in here by yourself."

"I was certainly not about to do something so uncouth," the Berserker pouted. "It was just that skinship thing."

"Ok, who told you about that?"

"Obviously it was that Tamamo," Georgios answered for her in a disapproving tone.

"Mhm. Anyway, I promised to introduce her to everyone else, so we should go," the homunculus sighed, though remembering to emphasize the need to fulfill a promise.

"Yeah, of course," Kiyohime replied, not inclined to argue since the set time had indeed ended.

"You'll stay here until one of us comes to fetch you, unless there's an emergency?" Gudako asked in a formulaic manner, which had been repeated many times by now.

"Yes. It's nicer here."

"Can someone explain all that for me?" the newest Servant of the group asked. "She's just here all the time?"

"The world outside is full of liars, and the wards make it nice and peaceful here, better than the Throne even," Kiyohime explained casually while pulling out a small notebook computer. "And besides, though the connection is terrible, I can still chat with my email friends."

"You might have guessed, but there seem to be some other parallel Chaldeas around, in fact at least one of them also has you," Georgios added. "That one, however, didn't seem to have Chloe, at least when they sent their Nero out to support us."

"We need to get going," Gudako interrupted him. "First off, we should meet my... it wouldn't be cousins, would it?"

"I don't know what would really fit best," the knight shrugged in his armor, which did not seem to encumber him at all. "But yes, we should get going. Have a good day, Kiyohime."

She simply smiled while waving them out of her room.

l

(Emiya Iri)

*knock knock* Ah, they're here!

Suppressing a momentary nervousness, the older of the two siblings cracked open the door to their room with a simple act of will before calling out to their visitors, "Please, come in."

Their half-sister opened the door a bit more, poking her head in, before letting everyone else enter; following Chaldea's First Master was a knight, one of its Ruler Servants, who stepped aside to reveal a girl, apparently about their age and wearing a uniform like she would have been going to school in were it not for the current situation.

"Hello," the new Servant said warmly, looking at her with some interest. "Sasaku."

"You look exactly like the picture," Matthew replied with some excitement, although this statement seemed to upset the person in question.

"Yes, I do-" She paused as a sudden flurry of wings revealed its owner, apparently a flying stick of some sort, which flew directly towards her; Iri snagged it out of the air easily, frowning in recognition of the Mystic Code's identity. At least, it should be the same one.

"Well hi cutie," Magical Ruby opened cheerfully while also dropping sparkles for additional effect. "Ever thought about becoming a magical girl? It's quite easy, you just need to make a contract wi-"

"No." She firmly rejected it out of hand.

"I'm telling the truth, you'd make a wonderful magical gi-"

"Not interested."

"Uh." Sasaku watched the exchange in some confusion. "You know her?"

"We know of her," Matthew replied. "A real troublemaker. Said Aunt Rin."

"Hah, I'm sure she wouldn't remember anything," Ruby contradicted him smugly, but actually making his point.

"Ahem." Taking custody of the wand and handing it over to its owner, Gudako tried to bring the introductions back from the sudden derail caused by its interruption. "Sasaku, let me introduce to you... huh? Oh, my bad." She paused to give them space to speak.

"Mhm. Iri, of House Emiya. It's a pleasure to meet you."

"Matthew, of House Matou. Similarly." Even though they had some time to prepare, his Matou-trademark purple hair had gotten out of hand again. Though no one was really thinking about such things at the moment.

"You might be wondering, so: our parents are Shirou and Sakura. Um, there was a specific arrangement to preserve the magus family lines," she remembered to clarify. Since the ones who would probably have done it before this point were not in attendance.

"Is there anyone from Tohsaka in Chaldea?" Caster asked. Oh wait, she changed Classes somehow.

"No heirs, if that's what you mean," Gudako sighed. "That was laid aside for Gudao even before he was designated to replace Siegfried as Second Master. Not that descent works the same way for us anyway."

"Did you already tell her about the Four Houses?" Iri prompted her.

"Mentioned it already, but... do we have any of the iconography around?" Shrugging out of her light jacket, scattering her light brown hair all about in the process, Emiya handed it over.

"Right." The homunculus flipped it around, looking for the patch on it. "Most of us here have something like this, since Chaldea is basically a joint project of all the Four Houses. Thus the shield, which is:"
Left half, vertical side-by-side: Green sword for Emiya and a light purple flower for Matou.
Right half, stacked: Dark purple circle surrounding yellow for Einzbern, and a solid red diamond for Tohsaka.

"It's the 'Four Houses Alliance,' jointly, which is party to all our relevant contracts, like with the magi here and elsewhere. Partially to obscure Emiya, which seems to have a reputation from my father's father, but largely for convenience since we're not really partitioned internally. Most homunculi outside of Einzbern or Chaldea are attached to the other three Houses, but that's to maintain integrity of the lines following, again internal, protocols from the earliest days. Obviously, no one outside of the Inner Circle knows about the Information Sharing, since that's a protected secret. Except for the two here."

"Can I ask how old you are? Not that much time seems to have passed," Sasaku wondered aloud.

"Twelve," Iri replied quickly.

"I'll be twelve in two weeks," Matthew added. "November 3rd, that is."

"I would be ten," Gudako volunteered for good measure. "But Siegfried, Gudao and I all entered the Inner Circle five years ago, so I've been 'on duty' since then."

"At age five?" the Servant asked.

"It's considered long for us," her Master shrugged. "And the relatively high weight the two of us get in the System isn't just fiat, if you were wondering. da Vinci might think so, but there's no magical 'key' that works like she seems to have misunderstood about what the Grand Aria is."

"I thought you said I had that access, in front of Kiyohime at that," Sasaku immediately pointed out.

"Ah. You see, admin privileges are... privileges. To some extent, you always had them, but simply weren't around. Put another way, the System is protected by its inherent structure, not keys, passwords or the 'right' ritual for access."

"We don't get it either," Matthew said in an encouraging manner. "Mother said it had to do with, uh. con-ver-gence?"

"Emergent complexity," Gudako helped him. "Matou wondered if they might be able to link into the system by using her magecraft to join with one of us, but the experiment failed because she simply couldn't understand on some base level."

"How do you all link then, actually?" Iri asked. "It isn't like telepathic magecraft?"

"Some sort of resonance effect, not unlike modern wireless communications perhaps? It's linked to us being weaker life-forms or something. Maybe. We know enough of its properties to use reliably and, yes, even set up the Grand Arias, but the how and why are a bit less clear."

Turning from the technical discussion, Sasaku's attention came back to her late students' children. "How come you two are at Chaldea, anyway? It doesn't seem like the place for, uh, casual visits."

Gudako didn't mind dropping the subject, since the people they had come to visit were clearly lost. "That's a good question; it was something small. Do either of you remember?"

"To talk to da Vinci," Matthew remembered a bit more quickly than his sister.

"We were on summer vacation. Of course, that would be in Germany, at the Einzbern Estate, and it's not far from there," Iri added. "And the Incineration just happened during the few hours that we might have been here otherwise."

"Oh right. That." Gudako seemed thoughtful for a moment before asking them, "Did they ever tell you what the tests showed?"

"What tests?" both of them said in near-unison.

"The Grail System currently only accepts as Masters special-type homunculi like myself, and humans from the Four Houses. It's a safety measure, since there a number of other magi here and we didn't want to take the risk of it trying to trigger the Holy Grail War and granting, more like forcing, Command Spells on outsiders. El Melloi's idea, by the way. Really competent, you'd like him. Also, I believe some of the women here would describe him as 'damn hot'."

"As a Servant, I'm definitely not looking for such information on humans." Sasaku stated flatly. There was a moment of awkward silence.

"By the way, will you be staying until Artoria comes to visit?" Iri brought it up cheerfully in order to change the topic. "She tells great stories, though it seems she has many problems ahead of her."

"Kiritsugu's Lancer, right? Or I guess she's a Saber now, from Georgios' story." She was about to look to him for confirmation, but the knight had quietly stepped out.

"She's different from what my mother told us from the Fourth Grail War," Gudako mentioned casually. "A lot more knight, a bit less princess now. Well, one might imagine her to be quite the downer, but it's the opposite since she literally has a Skill."

"I think she spends a lot of time with Scathach and Kojirou," Matthew pointed out, having watched many of their sparring sessions; though Chaldea's first Saber was the strongest of the three. "I wonder if he's taken to her."

Gudako glanced sideways at the Ruler in front of them before adding. "He's probably just... trying to cope. Ah, whatever. Ok, look, by the time they came back after her time at the Clock Tower, Saber and Tohsaka were a 'thing' as they say. Please don't get angry over it, since she's now... you know. Since then, Saber's gotten even deeper into his swordsmanship, which is saying something. Scathach was thinking that he might end up making more special techniques at this rate, a triple thrust to match his triple cut."

Sasaku blinked. "I kind of figured, yes. Wasn't sure if there was some reason you were trying to keep it quiet."

"Er, not really." Gudako was a little surprised by this reaction, or rather lack of it. "It would be surprising if the whole Clock Tower didn't know by now, considering how many idiots thought they could take on 'that swagging eastern familiar' and got trashed by him. We actually did get some good combat data on various runic defenses from him, since most of the troublemakers assumed he would be easier than Tohsaka; you know, since there's (Banishment) or (Dispel Magic)-type magecrafts."

"Didn't she have a Jeweled Sword?" Iri asked curiously. "I thought they make you really strong."

"They don't," Matthew said thoughtfully after a moment. "They only make generators now."

"Oh that is due to a diminishing returns effect. It's like digging wells; the more Swords you use in proximity, the less they can do. You can improve by using higher ply numbers, like digging deeper, but the result is pretty terrible if you use those. For example, Chaldea has eight of our best Blades, all seven-ply - firing one of those will take you out for a month. We have actually useful weapons for weapons."

"Guns?" Sasaku raised an eyebrow. "An interesting choice."

"Those are practically last-ditch weapons now. Shirou developed those during the Founding to help those of us with less magic circuits contribute against the likes of magi. The bullets are etched with runes of dispelling. We never used them since, it's like keeping World War 2 weapons as relics or for parades. Hmm, they are copies of World War 2 weapons, come to think of it. They do seem to reassure humans though, which since the attack has been useful."

"Did you find out who carried out the bombings?"

"No, they are either one of those in stasis or dead. Probably dead, if the mastermind set it up so that they would end up killing one another with their bombs. We checked everyone else with Kiyohime so we should be secure on that front. Mm, she was summoned, or rather messed with the Fate system to keep on getting summoned, after that so it's unlikely that someone would have known to take precautions against her, which would be hard anyway with how Servant-level abilities work."

"Kiyohi was rather bored throughout," Iri added, "Gudao said she had to listen to seventy people repeating the same few sentences over and over."

"Was necessary, though. While Servants don't get summoned unless they would actually contribute meaningfully, clearly our attempts to pick suitable humans were flawed since, you know, that happened."

l

(da Vinci)

"I've been wondering something," the Servant mused to one the assistants in her workshop. "I see where the other three Houses' magecrafts built up Chaldea, but Matou's one confuses me. What research were they doing since the Fifth Grail War?"

"That's an interesting story," the homunculus, Doru, replied after a moment, blinking purple-tinged eyes. "Because they hadn't borne fruit by the time the Incineration happened. You wouldn't be asking the question if they had managed to create an immortality option."

"I heard about that, but you know, brass tacks and all that." There wasn't much information, though it was probably present in those who had been associated with the House before entering Chaldea.

"Oh, well the basis of the magecraft is 'binding'. That isn't quite what the lost Einzbern Third Magic, which is supposedly the materialization of the soul, would allow. The issue is that, short of the Magic, there isn't any obvious way to get around degradation of the soul. Oh, unless you become a Heroic Spirit of course. Or use some loophole like Saber or Archer did. Archer's case is the more interesting of the two, but it doesn't give any answers."

"What did you do during your time there?" one of those from Tohsaka was examining a sample of diamond dust that had come back from the Generators. "I was involved in making the system Chaldea uses for its generators."

"I was in the group that was breeding phantasmals. Only for experiments, but there were plenty for any potential use."

"Hold on a second," da Vinci broke in. "Matou domesticated phantasmal beasts?"

Doru chuckled. "Hardly. In their natural state, you'd call them parasites. However, a parasite doesn't leech off itself like some sort ouroboros, so when you bind it, you end up with a tradeoff. Much like how your own flesh has to be kept fed, yes? Evolutionary speaking, the brain where 'you' sit comes with some high costs to the rest of the body."

"More like a symbiote then? What sort of mundane species is it closest to?"

"Worms."

A brief pause followed. "Phantasmal tapeworms?"

"They need magical energy to continue living on this side of the world. They have magic circuits, which you can use provided they are bound to you."

"Let me get this right," the Rider tried to clarify. "The House was breeding phantasmals in order to bind a lot of them, so as to bootstrap up the level of one's soul."

"Oh, Sakura already told us that isn't possible. It was already tried and failed disastrously."

"So what was the point, again?"

"Magical circuits not only are very flexible tools, but also amazingly dual-use. We thought that some of our number might need the help in order to join the Grand Aria, as we call it now, but thankfully the minimal capability any homunculus has is enough for that. Probably because it works off will and magic circuits are like antennae? Pretty much Matou took over researching souls, though not precisely the Third Magic; the Einzbern were researching ourselves, in a manner of speaking." He smiled wryly. "The humans destroyed a good bit that would have been useful, but it probably wouldn't have answered our questions. Still..."

"I thought the Grand Aria came from the Emiya side, since the base of that is commutation of the collective will and will of the collective."

"It's the more elegant system, I agree." Doru seemed content to leave it at that.

Of course, the curious mind can hardly be left half-satisfied. "Is the actual answer not covered by Information Sharing?"

"If it was, you should have asked in closed session," he grumbled for effect; da Vinci simply raised an eyebrow skeptically. She knew that Chaldea's homunculi were all covenanted into the Inner Circle, since they had been picked for the Project. And besides them and the Servant they were working under, no one else was in the workshop. In short, a flimsy excuse.

"It came about after we tried to form a network superintelligence," Doru finally answered. "Using the binding. It... didn't quite work as expected.."

"One second," his fellow interrupted him. "Are you talking about the accident that occurred several years ago?"

"There was only one worth mentioning, so yeah."

"I thought some of us died in that?"

"Yes? They, singular they now, happen to be quite alive, last I remember. But you wouldn't notice on the Fuyuki System because they're just another, single, individual now."

"So it worked?"

"Depends on your definition of worked." Doru paused, looking clearly uncomfortable. "I shouldn't say any more, since I don't know the details, only hearsay since I wasn't involved in that experiment. Suffice to say the Founder personally ordered that line of research closed. In any case, I was told that the head of Matou came up with the idea to use the Realm as a more flexible linking method - though it was actually Emiya who put together the actual system, as it was initially realized in Fuyuki, of course."

"I thought Matou had the best understanding of the Realm mechanics?"

"She did. It's still the case that their Houses are in personal union so it's more an accounting question which it counts for. Matou is supposed to be following soul manipulation, while the Grand Aria is a development of the Emiya-listed Realm methodology."

"Correct me if I'm wrong, but wasn't Tohsaka selling jewels and magical energy to the Edelfelt a thing? Most magi would kill for more magical circults, but the Four Houses didn't try to use those phantasmals?"

"No? In the first place, any outsiders getting them might be able to do the same thing, which means we'd be helping rivals - there's a general injunction against letting those outside of the Houses for exactly that reason. As for ourselves, it's sort of pointless?" Doru explained.

"Because they use magical energy to live?"

"We get a lot more from there just being more of us," someone helpfully pitched in. "Not only in terms of more people, but also each one actually produces magical energy and participates in the Grand Arias, making them much stronger."

"If we hadn't followed that route as aggressively as we did, the Separation Order wouldn't have worked and we'd not be having this conversation," Doru added. "Also, Edelfelt aside, the Einzbern side was handling most of the external trade. Most of our partners didn't realize anything had happened, I'd imagine."

"That's right," Shoha commented, having finished her inspection. "Besides, production numbers are misleading when you realize most of any House's output was done by us; we're all born in the Einzbern. I started off in one of the internal jewel production lines, before we developed the mana prism system the Four Houses use now."

"Aren't mana prisms just conveniently shaped jewels?" da Vinci questioned.

"It's like comparing a rechargeable battery to a disposable one. Edelfelt wants non-durable ones since they're weapons for them, which is great for us since they keep on buying the things." Shoha grinned, remembering some experiments from the past. "If we tweaked the Saint Quartz construction to be deliberately unstable, they might end up as the magical equivalent of an atomic bomb. That would be idiotically irresponsible though.