(Chaldea's Control Room)
"Well that's a new lower bound established,'' one of the operators from the Sensors section remarked as a report showed up on their console window.
"Hmm, probably because it is closer,'' the section overseer agreed. "Send a message to the Masters, non-emergency. We'll have an initial situation report by the time they get to Briefing.''
After a moment, the homunculus on duty, who was assigned priority System messaging privileges for this purpose, nodded to herself upon receiving an acknowledgment reply. "They're on their way.''
But the overseer was already deep in another discussion with Sensors. "I don't understand how it would look point-like, especially this close to Chaldea, we should have the resolution -''
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(Briefing Room)
"... as far as we can tell, it's the signature of a Grail fragment, almost entirely unobstructed so we're seeing it directly without the usual dispersion or shielding of a Bounded Field. This is probably the closest we've gotten to the infancy of a Singularity.''
"Great opportunity if we could deploy immediately,'' Agesipolis commented after da Vinci expressed agreement with the analysis. "Unless it's a trap.''
"I wouldn't be overly concerned about that,'' remarked Sasaku from behind her summoned Shielder. "There's very little actual space there, and no cover in Void Space for an ambush. Trying to be stealthy would mean having done a lot of work and concealed it all from Chaldea at extremely close range.''
"Hmm, if you say so,'' Gudao sounded skeptical but in truth Chaldea had already run all their various scans with high time-efficiency due to the lack of interference and didn't detect anything to suggest it the readings were being manipulated on the Event's end.
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("CBC'' Event)
"Looks like there's no choice, then. I'm not sure when we'll settle this, but we'll have to fight-'' The boy's piercing red eyes narrowed as he regarded the sword-armed Eastern saint opposing him.
"Yes... Looks like we'll have to get down to it,'' was the un-intimidated response as battle commenced.
However, not long after, a certain paladin broke into the scene with disruptive cheer. "Oh. There they are ! I brought a Master here ! Two ! Double the mastery !''
The Archer and Ruler simultaneously broke off their combat as Chaldea's forces quickly flooded the cavern. Gilgamesh looked over those present with an increasing sly smile but said nothing initally.
Amakusa decided to seize the initiative. "I see, we can tell the Masters why we need the Grail and let them decide in the end. Fortunately, I know how the Holy Grail works. It would be best if you let me handle the Grail.''
Gilgamesh hardly attempted to hide his amusement at this particular claim as his turn to speak came up. "Chaldea has quite a few Rulers and experience at handling Grails. Take for example that Ruler over there with the shady wand.''
"Yes, I'm here,'' Sasaku stepped forward, eyeing her counterpart, who in turn was unsure if his intelligence was being mocked simply by the presence of the magical girl diligently using her transformation's defenses as previously ordered by the Masters.
"You can't be serious,'' Amakusa Shirou muttered as his (True Name Discernment) delivered an unpleasant truth about the Ruler in front of him.
"In any case, I haven't made my case yet,'' Gilgamesh was at this point grinning. "You see, I was sent to fetch this Grail by none other than -the Holy Grail-. Well a terminal to be exact. But anyway Masters, you are the destination for this fetch quest.''
"You brat-''
*gunshots*
Amakusa made to cut down Gilgamesh by surprise but was immediately hit by a number of musket balls shot at him from further away. Laughing at him from behind the cover of Agesipolis' shield, Nobunaga couldn't help but take a musket into her own hands for emphasis. "Sorry, did your god promise you that one? I'd love to hear all about them... it's over.''
Swallowing, the Ruler decided on a gambit, simply throwing himself towards the Grail fragment.
Lighting her massive Ruby swordblade, Sasaku made to fly an interception, but Gilgamesh quickly caught her hand and whirled the two of them about to block Nobunaga and the rest of Chaldea from targeting Amakusa as he desperately clutched at the shard of light the pair had been feuding over.
"What are you doing ?!'' Sasaku asked while reflexively trying to throw off his grip.
"Relax,'' Gilgamesh whispered to her while looking over her shoulder at the other Chaldean Servants quickly moving up to close ranks around the Masters. "There's a reason I was delaying.''
"What... WHAT ?!'' Amakusa roared as something thick and dark exploded from the now clearly deceptively-bright shard, sinking into his spiritron body with hardly any resistance and quickly reaching his Spirit Core.
"You see, Chaldea,'' Gilgamesh raised his voice as the Ruler dropped to the ground, writhing as his Saint Graph was wrenched into a form far more foreign. "This Grail isn't the sort you'd want to drink from. Thank you, Amakusa, for demonstrating the consequences of doing so.''
"We probably shouldn't fight him here,'' Astolfo suggested on his way out. "Away !''
"That's an excellent idea,'' Agesipolis agreed, promptly moving to pick up Gudao while Nobunaga took hold of Gudako. Gilgamesh and Sasaku quickly followed the other five while still holding hands for some reason.
"I only count four Servants, so you should have at least two more,'' the Archer observed as they made their way out of the cavern Astolfo had led them into. Fortunately leaving was much less complicated as the branches only spread out downwards and they were headed up. "Please tell me one of them is a heavy-hitter.''
"The best,'' Agesipolis replied for the Masters. The seven of them soon saw daylight ahead and moments later were in front of Artoria and Stheno who had been left to stand guard.
"I take it something bad is headed our way,'' the Greek one said with an air of the uninvolved.
"Someone seriously overdosed on bad Grail energy, you know. Please prep Excalibur.'' Gudako explained and directed the group's Saber while Gudao quickly arranged the other Servants into a defensive formation.
"I suppose that terrible wail is it?'' Stheno asked as sound she mentioned reached everyone's ears.
"Obviously. That energy signature is coming up pretty rapidly now. But we had all the time we needed. Ready, Artoria?''
The Princess Knight only nodded to Gudao's question while raising her Holy Sword with an air of concentration.
With a dramatic flare, the Master pointed towards the shaking cave entrance and used a Command Spell. "Hit it !''
"(Excalibur) !''
The weapon swung down, unleashing a torrent of magical energy that the onrushing corrupted Amakusa could not evade. There was a great rumbling in all the land about the Chaldeans as a physical shockwave bounced back out of the rocky ground. However, everyone's weapons and Noble Phantasms remained trained on the potential threat vector.
A few seconds passed before Gudako shrugged. "Looks like... there's just the small remnant left. Which should be the last bit of the Grail fragment.''
"Perfect, we just need to dig it up, and of course confirm that Amakusa's signature is gone, and this outing can wrap out,'' Nobunaga sounded quite positive, though her guns were still at the ready. "By the way, where did that paladin go?''
"I think after we blasted the target, he hopped on that Hippogriff and left,'' Agesipolis noted.
Gilgamesh took out what looked exactly like a golden shovel. "Alright, give me a while to dig it out and I'll get this quest done.''
"Oh, I can help with that,'' Sasaku offered.
"There's probably Grail mud all over and I'm sure your Kaleidostick would rather you not get that dress dirty,'' the Archer refused her. "I've got to at least do this bit for it to count, so just keep watch for any intruders.''
"We can secure the perimeter,'' Gudao said. "Eh, might as well also harvest any useful materials that might be about.''
"Never one to miss the opportunity to 'farm mats' as da Vinci would say,'' Stheno frowned at the task. "Maybe I could swap with your watch?''
Gilgamesh brushed off the Assassin's attempt at a manipulative smile. "There might be wyverns, you know. Better keep that head on a swivel.''
Gudako thought for a moment before organizing her group without comment. She might not be able to stop him from taking off with the fragment, but depleted as it is there's not much to gain from trying to swipe it from under us. Or, more likely, he wants to be able to talk with her semi-privately.
"Ahem. While clearly drained, as it was formerly filled with corrupting energies, I think you'd agree with me that this is the better state to deliver it in.'' Gilgamesh had tried to brush off some of the loose dirt and Grail mud mixture, but not overly successfully visually speaking.
"Oh, I agree.'' Gudao eyed the item in question; it was a bit less bright compared to when they had first seen it, but it had not been filled with anything good then either anyway. He motioned for their Ruler to take it into custody which she did quickly.
"So quest completed, we all done here?'' Gudako asked the Archer. "We can't exactly hang around much with the Grail in containment now.''
"To avoid annoying timeline shenanigans, I'd prefer to return to the Throne before you end your Rayshift back to Chaldea,'' Gilgamesh replied briskly. "But to also avoid contamination of your system, it would be ideal if I washed off some of this before we shook on it.''
Gudao looked to some of the other Servants but they didn't have any particular insight to give. At least it wasn't a particularly high-stakes ask since there was no real cost to waiting provided they prepared for an orderly exit.
"I believe it would be best to get a clean last state linkage,'' Sasaku spoke up after a while. "If you recall our experiences with Elizabeth and so on, the system tries to pull our very last experienced version of any Servant.''
"It's a good side-benefit of our Grail System,'' Gudako agreed, giving her approval. "Well no time to waste, go take a shower or whatever.''
"Much appreciated,'' Gilgamesh started off downwards from the cave entrance headed towards where the group had earlier identified a small stream. "Come along.''
Nodding quickly, Sasaku gave the Masters a moment before quickly following the boy.
"Hmm. Well let's prep to leave, then we'll wait until they return or we have to get out,'' Gudao started planning. "Though I daresay everything is in order already.''
"Yes,'' Agesipolis confirmed without pausing his watch of the surroundings. "As none of the sensors have picked up anything of note, we should be good to go anytime.''
"Good, we're on time.'' Gilgamesh reappeared, trotting up towards the camp with Sasaku in tow. For reasons of his own the Archer had apparently discarded his shirt as a lost cause rather than attempt to wash it, clearly showing the Chaldeans the striking red markings across his bare chest and torso along with a necklace of some sort - probably a 'minor' Noble Phantasm to the King of Heroes.
"What, did you just strip and jump into the water?'' Stheno's general dislike of men apparently now extended to the boy. Though she certainly tended to like cute things, he had earned a place in her list of not-cute things.
"You'd love to see it.'' Going by his prior responses, this antipathy was mutual, Gilgamesh having had bad experiences with goddesses in the past, as he might put it.
"By the way, do you have anything we can use as a catalyst? Even with one it isn't guaranteed but,'' Gudao paused as the Archer reached into his pants pocket and pulled out a golden ticket.
"I've already given her something for that. But there've also been additional arrangements,'' he explained. "I just need to ensure that current-me is in the Throne and thus available to be summoned before you get back to Chaldea. If so, you'll definitely be able to pull me from the Throne's list whenever you do the ritual.''
Gudako subtly shifted her line of sight to the indicated Ruler who nodded slightly in response; the Master noted that at some point she had changed back into her uniform; Ruby was as usual absent, the wand's presence only being necessary when transformed. "Go ahead then, we'll wait for your signature to disappear before we end the Rayshift.''
"Great.'' Gilgamesh tucked away his Summoning Ticket. "See you around.''
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(Back in Chaldea)
"Can you handle the initial debrief on this one?'' Gudako asked her partner. "We'll deliver the Grail fragment to a pre-check containment Vault as usual.''
"Certainly. Everyone else, you know the routine; materials to the standard drop off then you have the day off.'' With sounds of agreement, everyone set about their different tasks.
...
"By the way, what item did Gilgamesh give you?'' Gudako remembered after a couple of corridors. "I forgot about that, but we need to have it checked too.''
"It, uh, wasn't exactly an item,'' the other girl replied evasively. Gudako simply stopped and stared at her until Sasaku sighed and continued, "I know this sounds stupid, but it was literally a 'first kiss' thing.''
"That's odd,'' Ruby popped up to add. "Since even with only this summoning, I'm pretty sure that Chloe already-''
"Oh be quiet Ruby,'' its owner half-heartedly swatted it about a little. "I said he gave. But to be honest, I think he was just messing with you about that. After all, he had that Ticket.''
"Messing with me huh? Actually, if he already had that ticket, why jump through hoops?'' her Master asked the obvious question.
"What's to say he actually had it before finishing? He did only say there had been arrangements, you can easily imagine that it only arrived in his possession afterwards.''
Gudako eyed the currently quietly fluttering Ruby warily before making her decision. "I ... well there's no good way to be both tactful and unambiguous about this, so I'm going be explicit just the once,'' she said deliberately. "Ok. If you don't want to be Gilgamesh's wife, we can do something.'' Who exactly we was, she left unsaid.
"Bear with us for a sec, Ruby,'' Sasaku murmured before falling silent for a few seconds first. "Did I give off the impression that I was hoping for intervention?''
"Uh, well I'm not well versed in human relationships-''
"That makes two of us non-humans then. Just answer the question.''
"Well, no.''
"I see. Fine, direct for direct. I don't want anyone to do get involved. You've definitely misunderstood our relationship. That's all.''
Glancing over at the Kaleidostick, Gudako raised an eyebrow. "Nothing to stir the pot with for once? Actually come to think of it, shouldn't you have some angle on this?''
"As a famous magical girl once said, 'Magical girls should only fall in love with each other (heart)' but don't expect me to jump into this particular pit of worms,'' Ruby replied with uncharacteristic seriousness to end with, if not start.
Sasaku make an amused sound. "In case you were wondering, Gil isn't part of the group that's backing Chaldea; it's actually his older version. Along with uh, who did he say, Zelretch, Chloe, Merlin; we had ideas about all those, but also: the Holy Grail (represented by a Terminal), Solomon the King of Mages and probably some others he hadn't met.''
"Hmm, the Holy Grail's Terminal, wouldn't that be a Ruler? But somehow in Chaldea you're the Ruler designated by the Grail as 'Overseer' for all that we were going for months and three other Rulers before you arrived.''
"Gil mentioned that the Holy Grail is only one variant or version of some greater wish-granting archetype, concept, entity; I have no idea though, but perhaps it didn't trust the various Rulers who serve some god that's presumably not part of the group. You know, the one that sent Amakusa into the previous War to eliminate me.''
"Mhm. I take it you'd prefer that the two of us left the next few summoning sessions to you?''
"That's a good idea.''
"Sure. Well, we do want to maintain neutrality in these things, but either way you should know that, if anyone, Matou will probably take it pretty personally for some reason that Emiya didn't share with us. It doesn't seem to be related to the one we know, but in any case you're the one best able to handle her. For many reasons.'' The homunculus fell silent.
"Understood. I'll leave it to your tact to avoid any further misunderstandings.''
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Notes:
In general, you can take dates as being similar to the original Japanese FGO server + 4 years. By the way in Materials, it is labelled under Events as "Amakusa Shirou Trial Quest" which is not very inspiring.
In fact, Amakusa has seems to possess neither Divine nor Riding traits. Not that Nobunaga was super-effective against him in this story anyway.
For the curious, read "before you end your Rayshift back to Chaldea'' as like "before you travel back to Chaldea''. Similar to Rayshifting in, ending a Rayshift involves something traveling back to Chaldea (that's why they remember everything and have the materials - those that do make it back with them anyway).
By the way, Ruby references something that Testament said in the FGO Prisma collab event. It hasn't actually happened in this story's timeline yet, but obviously with the likes of Ruby and Chloe, it'll be rather important when it does.