New story time, go!

So yeah, this has been rattling around in my brain for months now. I've finally got the stuff that was keeping me from writing kind of sorted out so this is happening now. I've got things planned out pretty well, so hopefully updates can happen kind of regularly. Let's go.

SPOILER WARNING: Fate/Stay Night (all routes), Hollow Ataraxia, Fate/Zero, and of course RWBY up to volume 3 are fair game for spoilers. You have been warned.

PART 1: From Shadows

Chapter 1

I struggle with the chain wrapped around my arm, trying to unwind it so the King of Uruk could be swallowed by the grail. Dammit, for a king and a ridiculously powerful heroic spirit, this guy sure was being a sore loser.

"Dammit, are you trying to pull me in with you?" I shout angrily at the ancient king.

"As if I would allow myself to be killed here, mongrel! Now stay there until I pull myself out!" comes the bastard's reply.

Seriously, this guy…

"As if I'd let you! I'll cut my own arm off first!"

I don't particularly want to cut my own arm off, but I can't exactly stay put here much longer. I'm barely even standing at this point, after all. And, if I get pulled into that void… The grail would be able to use me as a substitute core. If it means saving the world, I'll gladly give an arm.

I hold out my right hand, my overused circuits flaring to life-

And then they cut off. Bakuya fails to form in my outstretched hand.

Ah. That's right. I ran out of mana. My magic circuits are completely dry. I try to draw on my contract with Tohsaka, only to find nothing on the other end. Seriously? Is she…?

I want to mourn, but there's no time to think about that now. First I have to stop this guy. But it looks like all options are closed to me.

Well, that's not quite right. There is still one option left to me. I concentrate, and a familiar feeling of steel being poured down my spine wracks my body with pain. My makeshift circuit, formed of my own nerves. It was pretty ironic, that after all of my progress in this war, I would fall back on my old, pathetic methods.

I can't project a blade. The only magecraft I can perform with this false circuit of mine is structural analysis and reinforcement. Projection is beyond me.

However, reinforcement is all I need.

Reinforcement is a delicate process. If too little mana is used, it will have no effect. If too much is used, the target of the reinforcement will detonate. With my lackluster circuit, it would be a matter of luck to be able to properly reinforce myself.

But, I don't need to do it right. I pump mana into my arm, heedless of the possibility of over-reinforcement. In fact, that's my goal. The amount of mana I'm pumping into my arm is more than enough to blow my arm off my body, letting Gilgamesh be pulled into the grail.

Then, suddenly, there's a popping noise from my back. It's not a loud noise, but it sounds deafening to me. There's a sharp pain in my spine.

I'm distinctly aware of all my injuries. Every part of my body burns, the pain of my magic circuits being overused. I've got dozens of scuffs and bruises covering my form. I can feel every inch of my frame, in pain.

So why can't I feel my legs?

I find myself falling, being dragged towards the hole from the grail. I need to stop myself, but I can't move my lower body at all.

Oh. I get it now. My makeshift circuit that Tohsaka had warned me about using… My spinal column must have burst from the pressure. Dammit… to fail like this…

The grail swallows both of us up, and darkness envelops me.

My vision fades into focus, my eyes locked on a small white-haired girl, surrounded by strange, wolf-like creatures as snow falls from the sky.

"Il…ya?"

My adoptive sister, surrounded on all sides by these creatures. Obviously, I won't stand for something like that. The familiar forms of Kanshou and Bakuya form in my hands, and I spring forward, reinforcing myself as I go. For some reason my movements feel off, but I shove it out of my mind for now.

I hurl Kanshou, the blade spinning through the air and cleaving through one of the wolves like butter. As the blade flies back towards me, I notice that the wolf is dissolving into a black mist. Guess they're magical in nature, huh? I catch the sword as I close into melee range, assuming the fighting stance I had copied from Archer. I may hate the bastard, but I have to admit his fighting style comes in handy. If it even is his. I bet that idiot just copied it from the Archer of his grail war.

The creatures pounce at me, but each one lunges for the fake openings included in Archer's fighting style. The gaps in my defense close before the attacks reach me, and in short order I've annihilated the beasts. I turn to Ilya, my golden eyes meeting her… blue eyes.

Ah.

This girl… isn't my sister. Ilya's eyes are red.

Why did I even make that mistake in the first place? I remember now… Gilgamesh killed Ilyasviel. He tore her heart from her chest after maiming her and killing her servant. You'd think something like my sister being murdered in front of me would stick out in my memory more.

Speaking of my memory… when had I learned she was my sister? She had never mentioned anything like that during the grail war. Did Kiritsugu mention it at some point? My head hurts… why can't I recall anything before the start of the grail war? There's an empty space where my memories should be, between being saved by Kiritsugu and when I summoned Saber. All my memories of that time… are gone.

I'm brought out of my thoughts by the ground beneath me shaking. I turn just in time to see a massive insectoid creature erupt from the snow behind me. It's got a centipede-like appearance, but with a more defined head and face. The insect has the same coloration and markings as the wolves from earlier, but parts of its body segments are glowing red. The snow it tosses up into the air is quickly reduced to water vapor- this creature is radiating an incredible amount of heat. This thing seems to be of the same ilk as those wolves earlier, so there's no way it isn't hostile. I start to think of how I can fight this thing.

My mind runs across a list of numerous noble phantasms I could use at lightning speed. With the heat it's radiating I doubt a long drawn out fight would end well for me. I need to end this in one decisive blow – that eliminates a good number of my options, including Kanshou and Bakuya, so I let the married swords dissipate. Similarly, I don't have time to get to an optimum range, so my heavy arrows like Caladbolg are no good. This thing won't meet the prerequisites for Fragarach… I don't even know if it has a heart, so Gae Bolg is out as well. Assassin's Tsubame Gaeshi could work, but I'm not sure if I could pull something like that off without breaking my wrists.

Finally it hits me. A nameless stone blade appears in my hand. It has no special properties, but its user was a demigod known for his strength.

"Trace, on. Trigger, off. Nine Lives Blade Works!"

I unleash on this centipede thing the same technique I used to protect Ilya from a rogue Berserker – that never happened so why do I remember it so clearly – unleashing a flurry of simultaneous strikes on the creature – one for each segment of its body. The technique had been different when used on a human shaped target like Berserker, but it was still the same technique – the total annihilation of a target by numerous attacks, performed in the same instant.

The creature's exoskeleton cracks, fire erupting from its wounds. However, it's still moving. That shouldn't be possible. I'm certain I hit it with maximum force, so it should have been blown away. I prepare to unleash a second flurry of blows, but the axe-sword has fallen from my grip.

…It seems I overdid it on that attack. My arm is completely broken. I thought I was using safe levels of force, but I must have overestimated my own durability. I have to keep fighting though, so I project a new weapon in my other hand. I need something that can be used with one hand and cut through this thing's ridiculous defenses.

"Balance yourself for one hand, Durandal." I intone as I project the blade of Roland. One wish granted by the blade should make it usable in my current state. And now… "Cleave the enemy's defense, Durandal."

I circle round the beast looking for an opening within the torrents of flame gushing from its body.

…Seriously, what the hell is this thing?

The insect is the one to make the first move, charging at me, gaping mandibles aimed at my neck. I dodge its mouthparts, but I'm still sent sprawling. It coils and prepares to make another attack. I start to stand up as it rushes forward, when suddenly, in a flash of steel and feathers, a man appears before me, deflecting the creature's attack.

"…Seriously though, what's a Remorhaz doing this far south?" He mutters, tossing his sword into the air. Its form expands into a scythe and he catches it with his mechanical right arm, twirling it dramatically. His white cape flutters in the wind as he glances over at me.

"Alright kid, you can take a break now. Let the grown-ups handle this one."

He leaps into the fray, some sort of bounded field projected around his body deflecting the fire. It quickly becomes apparent that this titanic creature is no match for this single man. I collapse back into the snow, grateful for the reprieve. I'm exhausted. Finally, as I sit there, the reason for my movements feeling off earlier and my attack failing against the creature hits me. My body has been shrunk.

Well, it's more accurate to say I've grown younger. I haven't just lost years of memories, I've lost years of aging too. After a brief moment of shock, I find the words to sum up my predicament.

"…What the hell?"

A/N: So yeah, that happened. Any questions?

"Why does Qrow have a mechanical arm and what the hell is he doing in Atlas!?"

Good question. Let me answer it with one of my own.

Why should Shirou's arrival be the first change to Remnant's timeline as the result of the grail?

In other words, other things have changed beyond his arrival and we'll get into that later!

"Nine Lives Blade Works doesn't work that way!"

Ah but it does, dear reader! Nasu's statement on it is that the version of the technique used on berserker was the "Anti-Unit" version. Here, Shirou uses the "Anti-Beast" version of the technique, similar to the style's origin of slaying the Hydra's hundred heards in one instant.

"WTF is a Remorhaz!?"

It's a monster from Dungeons and Draagons! Feel free to google it and imagine it grimmified if you want.