Disclaimer: I do not own the Fate franchise it belongs to Kinoko Nasu and Type-Moon. I also do not own Touhou Project, it belongs to ZUN.

The Scarlet Vampires Incident

Prologue

"If something is worth doing, then it is worth doing right."

The classroom was packed to the gills, with tables meant to be shared by four students now sporting six or seven or even eight students each, while the steps that ran up and down the amphitheater-like classroom had students sitting on them as well, notebooks and other materials balanced on their knees. More students sat along the edges of the ground floor, along the walls and immediately before the first rank of seats and tables. Others stood at the very back, against the wall, straining their eyes and ears if not outright reinforcing them to catch what the instructor was saying and writing on the board.

Now who might this so-greatly esteemed instructor be, that the classroom was filled beyond its normal capacity?

Who else could it be? He was Kischur Zelretch Schweinorg, Master of the Second True Magic 'Kaleidoscope', Wizard Marshal of the Mages Association, Slayer of the Crimson Moon, and the greatest practitioner of Jewel Magecraft the world would ever see and know.

He had appeared out of nowhere, as he usually did, informing the surprised lords and department heads that he had come seeking a new batch of apprentices. This had thrown the entire Clock Tower into turmoil, as the lords, department heads, and other brass hats and big names present immediately began pushing forward recommendations and dossiers for their heirs, relatives, students and apprentices, all seeking a chance to share in any small way they could in the prestige of being known as connected to an apprentice of the nigh-legendary Wizard Marshal.

Granted, only a few of them would actually be chosen, and those that would be faced great risk and hardship. Those that would be apprentices to a magician faced a VERY large chance of going irrecoverably insane, and while that did not apply to those who would be apprentices to a magus, the Wizard Marshal had higher standards than most, with many if not most flunking out due to their inability to keep up.

Those that could though, well…

…they would become among the greatest magi of their age. And that was enough for everyone with a big name and those with small names but great ambition to take the risk.

All that aside, however, the Wizard Marshal had also stated that while he was considering apprentices, he would also be holding lectures on Jewel Magecraft, open to members of all departments willing and able to attend. To minimize the bureaucratic difficulties and risks of inter-department strife, the lectures would be held not at the Department of Mineralogy as they would usually be – Jewel Magecraft falling under that department's purview – but at the Department of General Fundamentals.

Each and every class was simply overwhelmed by the sheer number of students, even those who did not normally study Jewel Magecraft. A chance to learn from the Wizard Marshal was not something to be passed up, after all.

At present, the Wizard Marshall was currently lecturing not on the mystical properties of jewels, their applications and conceptual natures…but on their physical and chemical properties, the processes of their formation, their sources, how to identify their quality and how to tell the various kinds of jewels from each other…

…all in all, not much different if at all from a mineralogy class held in a mundane university.

Very basic for those present, especially those from the Department of Mineralogy. No one complained though, and notes were taken near-religiously and every bit of critical thinking ability the students possessed bent on the lectures provided by the Wizard Marshal.

If the Zelretch decided he wanted his students to go back to the basics, then by God they would go back to the basics.

"…the magma will flow towards the break in the Earth's crust, and thence towards the surface." Zelretch was saying. "There, the temperatures and pressure will be insufficient for complete crystallization. Instead, the magma will cool into fine-grained rocks, with crystals distributed across the interior. These are what we call phenocrysts. Among the crystals or should we say jewels that can be commonly found in phenocrysts are corundum, moonstone, garnet, and zircon. Rubies and sapphires may also be found in phenocrysts, with Thailand especially having rich deposits of ruby and sapphire-bearing phenocrysts."

As Zelretch continued to speak, the air to one side of the teacher's desk seemed to twist on itself, and then to the alarmed responses of Zelretch and his students, split open. As though a scalpel had been delicately sliced into the fabric of reality itself, an incision was made and then carefully pulled open, exposing an area of utter darkness beyond, so black as to be like a hole in reality (which it was).

And then to the horror of the students, eyes opened inside the darkness, staring out into reality.

Zelretch though, didn't seem concerned at all. If anything, the moment the eyes opened, he seemed to relax, and setting down the chalk he was holding, fixed his collar.

"Kischur?" a woman's voice asked from the darkness, as red ribbons appeared out of nowhere and tied themselves into pretty bows at the ends of the split in reality. "Are you there, Kischur?"

"Yes, I am here." Zelretch replied with a cough and a smile, before stepping forward.

Mouths fell open as a beautiful blonde woman literally floated out of the hole in reality, wearing a pink dress with black cuffs under a Chinese tabard, along with a pink mob cap on her head. She twirled a pink parasol over a shoulder as she floated to a halt in midair, and then steadying herself, gently landed on her feet.

"Yukari!" Zelretch said with genuine delight as he approached. "It's been such a long time!"

"My, my, it has indeed." The blonde woman – Yukari – said with a giggle before pecking Zelretch on the lips. "You've gotten old, my dear friend."

Zelretch laughed. "Time passes." He said with a hint of sadness. "But you my dear, you haven't changed in over eight hundred years. You're still as beautiful as you were back then, under the light of the Moon, in the gardens of Jiangnin."

"Oh my," Yukari said with a blush and a giggle. "You're still such a flatterer, I see. But thank you."

Zelretch and Yukari Yakumo smiled happily at each other, much to the mortification of the students. Their public displays of affection aside, it was common knowledge that the Wizard Marshal was old, and judging from what was said between them…

…this paramour of his, her appearance aside, was likely just as old as he was.

Blinking, Zelretch turned his attention back to his pale and shocked students. "Ah yes, ahem," Zelretch said without a trace of embarrassment. "Class dismissed, we'll resume where we left off tomorrow morning."

The students immediately and hastily began vacating the classroom, while Zelretch turned back to his old flame. "So," he began. "To what do I owe the pleasure?"

Yukari pouted. "Can't I come and visit an old friend when the opportunity comes calling?" she asked. "We're both usually quite so busy, you know."

"True," Zelretch sighed, and allowing a rare show of how much of a burden being the Second Magician was. "And I'm happy to see you too. I really am."

Yukari smiled sympathetically, and placed a hand on Zelretch's cheek. Zelretch smiled back, and taking Yukari's hand squeezed gratefully before she drew it back.

"Anyway," she said. "I do have something of concern to tell you. Well, not really, it should take care of itself, but I thought you should know regardless."

"Oh?"

"There's been an incident at Gensokyo."

"Then…from your words I imagine the Hakurei Clan should be able to handle it quite well. If so, then…?"

"The Hakurei…?" Yukari echoed. "Oh yes, of course. Reimu should be able to deal with it easily enough. Or that Shinigami, Komachi Onozuka I think it was…but that's on the other side of the veil."

"…what happened, Yukari?"

"Patchouli ran an experiment that rather went out of hand." Yukari said. "No, no, it's alright. Nothing disastrous…apart from swapping Miss Scarlet and friends and their mansion with another spot on this side of the World."

"…Scarlet…the Scarlet Sisters are back…and you don't think that's a serious matter?"

"I've looked into the gaps between timelines," Yukari said. "Remilia has no interest in staying on this side of the World in any of them, and Patchouli should be able to figure out a way to get them back into Gensokyo in a bit."

"…hmm, I'll check the timelines later, but I'm still apprehensive about letting the Scarlet Sisters run wild. Remilia Scarlet in particular, has a very dangerous ability, as you well know."

"Fate Alteration," Yukari murmured while nodding. "It's not much of an issue in Gensokyo or anywhere else on the Reverse Side of the World, but here…"

Zelretch sighed, and then offered a smile to Yukari. "In any case," he said. "While I do have my concerns, it's not that I doubt your judgment. I'm just playing the Devil's Advocate."

Yukari laughed. "Yes, I know." She said. "Always so responsible, aren't you, Kischur?"

"Of course I am." Zelretch said with a rare air of bravado…though it was completely true. "Anyway, shall we discuss this somewhere else more…private, and comfortable?"

"Why yes," Yukari said, taking an offered arm from Zelretch while closing the gap she'd arrived from. "I think we should."

"Then let us go."

"Yes, let's."


Let silver and steel be the essence.

Let stone and the Archduke of Contracts be the foundation.

Let rise a wall against the wind that shall fall.

Let the four cardinal gates close.

Let the three-forked road from the crown reaching unto the Kingdom rotate.

Let it be declared now: your fate shall serve under me, and my fate shall be with your sword.

Submit to the beckoning of the Holy Grail.

Answer, if you would submit to this will and truth.

An oath shall be sworn here: I shall attain all virtues of all of Heaven, and I shall have dominion over all evils of all of Hell.

Yet you shall serve with your eyes clouded by chaos, for you would be one caged in madness, and I shall wield your chains.

From the Seventh Heaven, attended to by three great words of power, come forth from the ring of restraint, Protector of the Holy Balance!


"Hasn't Patchy made any progress yet?"

Two people walked down a hallway carpeted and wallpapered in red, great glass windows staring out across the mansion grounds to the suburbs beyond the property wall. Well, one of them walked. The other just floated through the air.

The one who walked was a maid, wearing a dress of dark blue with white trim, under a white apron and a matching headband. She had red eyes and silver hair, the latter tied up into braids with green ribbons. She walked slowly and elegantly, hands held folded politely over her lap.

The one who floated was a little girl, about nine-years old in appearance. She wore a pink dress with red ribbons around the sleeves, and tied at the waist with a red sash. Her eyes were red, and beneath a pink mob hat decorated with another red ribbon her short-cut hair was colored pale blue. And from her back, there stretched a pair of bat-like wings wider than she was tall.

"Lady Patchouli has admitted to necessity of delaying our return us to Gensokyo." Sakuya Izayoi replied. "She expressed concern over the delicate nature of space-time conversion, in particular over the likely outcome that a mistake could lead the mansion to either be trapped in null space for an indeterminate period of time, or to simply be reduced to component atoms that would be scattered across the entire space-time continuum."

"…fine." Remilia Scarlet grumbled. "In any case, it's probably for the best, as otherwise all that work we put into getting that man into shape to win the Grail for us would have been for nothing."

"As you say, my lady." Sakuya said.

"How's that little girl I asked you to take care of?" Remilia asked.

"She is sleeping." Sakuya replied. "It is late, and it would be improper for a child of her age to be awake at the present time. In the future, when she gets older, then things will be different."

"Fair enough," Remilia said. "She's a vassal too, so I suppose I shouldn't push her health too much right now."

"Yes, it is as you say, my lady."

Remilia nodded. "And how's her lessons going?" she asked next.

"Lady Patchouli remarks she's studious enough." Sakuya said. "She's having difficulty with the Roman alphabet, but her kana is good, and she's making good progress with basic kanji. And apparently, she does well in basic arithmetic as well."

"And magic-wise?"

"Lady Patchouli has her practicing her prana control through projection and reinforcement exercises." Sakuya replied. "However, Lady Patchouli has also stated that until Sakura's prana control has reached a certain level, she will not teach her anything more than that."

"Well, if that's what Patchy says, then fine."

"Yes, my lady."

The doors into the throne room opened, and entering Remilia picked up speed to reach and then sit down on her throne atop its dais on the far end of the room, flanked by crimson drapes. Sakuya took her place at her mistress' left, and after a moment Patchouli Knowledge emerged from the shadows to stand to one side of the carpeted aisle leading to the throne from the doors.

"How did it go, Patchy?" Remilia asked.

"The summoning was a success." Patchouli answered laconically, and Remilia grinned.

"Good, very good." She said, settling back on her throne. They waited for a few moments, and then the throne room doors opened. A man entered, the doors closing silently behind him. Dressed in a butler's outfit, he walked up the dais, and then placing a gloved hand on his chest, Kariya Matou sank to one knee.

"Show me your Servant, Kariya Matou." Remilia commanded.

"Yes, my lady. Berserker!"

There was a flicker of light, and then a towering, hugely-armored knight appeared next to Kariya, shrouded in shadows. His visor glowed an ugly red, and after a moment grudgingly sank to one knee as well.

"Can you control him?" Remilia asked.

"His power is great, and his insanity even greater." Kariya replied. "But compared to Miss Meiling's battle fury…it's very manageable by comparison."

"Very good then," Remilia said, sitting up on her throne. "Bring me the Holy Grail, and you shall have as I promised. By the inescapable power of fate, Aoi Tohsaka and her love shall be yours, now and forever."

Kariya bowed his head, the faintest hint of triumph masked by self-control born of time-warped years of training by his masters.

"It shall be as you command, Lady Remilia."


A/N

I've been toying with this idea for months, and it's finally ready.

It's not a pure Touhou and Nasu crossover, as several fellow fans of Touhou told me not to apply the light-hearted theme of Touhou too strictly. It should still be there, but downplay it. Don't make it too important, and keep things serious when needed.