Fate Stay Night - Visitor from the Void

Chapter 2 - Welcome to Nasu's World

...

Well, this is certainly and odd turn of events. First, I have a trippy dream that looked like something someone who did PCP would see. Then, I wake up in a massive bedroom, most likely in a mansion. Now, I'm staring at the 'Little Murder Machine' herself, Illyasviel von Einzbern.

Have I been isekai'd? Or is this just some weird fucking hallucination?

I suppose this isn't all bad, in retrospect. I mean, Illya was my favorite girl in Fate/stay. Rin, Saber and the others were cute, but Illya was my favorite. Shame her route was cut.

I'm not a lolicon, I swear.

Downside, and this is a big one, I've been reincarnated in the Nasuverse. The Grail War? Wholly insignificant compared to the Moon Cell and the 40-meter long alien from Mercury off in South America.

This world, or perhaps worlds, are bat-shit insane death worlds on par with SAO.

And I just so happen to be staring dead into the beautiful, yet terrifying crimson eyes of a sadistic murder-loli.

"Erm... it's nice to meet you too, Illyasviel." I say, trying to be a bit polite.

"Oh, just call me Illya, Onii-chan!" She smiles again. God she is so cute. So, I shan't be deceived by the cuteness!

"Oh right, I never to you my name. I'm Samuel Rivers, but most people just call me Sam."

"Sam-onii-chan, then." She says again. Hang on a sec-

"Why are you calling me 'onii-chan' when your name doesn't sound Japanese at all?"

"My mama's side of the family is German, but my papa's is Japanese."

"Ah, that'd do it." I forgot that little detail.

"But are you sure you're okay? Liz did find you freezing to death outside." Say what?!

"Freezing outside? Where am I exactly?"

She tilts her head. "You... don't know?"

"Last I checked, I lived in Louisiana, in America. Not much snowfall there. On top of that, it's summer."

"You really are out of it, Onii-chan!" She says with a cute giggle. "You're in my family's home, in Germany." Yeah I figured I wasn't home. "Also, it's October, nowhere near summer."

"October?!" I slightly shout, eyes wide. It's supposed to be fucking June!

"Yup! October!"

"Great, first I have a crazy-ass dream, now I'm halfway around the world and four months into the future." I say future, but I know I'm in the past, unless Fate/stay canon has changed from January 2004 to 2022.

"What's this about a dream?" She inquires.

"I had a weird dream before I woke up here. I was in some kinda void. Then this ball of light showed up and I touched it. The ball disappeared and I saw a bunch of stuff fly past me. Eventually, it all became too much and I woke up."

"Ball of light? That sounds like-" She cuts herself off as her eyes widen. "Did you touch the Root?!" She shouts.

"I guess?" I ask, uneasily.

"This is unbelievable." She says, frustrated. Should I tell her about Fate/stay? I mean, Second Magic exists, so hopefully it won't shatter her world-view.

"You wanna know what's unbelievable? Ending up in the world of a series you're all too familiar with."

"What?"

"Well you know about Second Magic?" She nods, confused. Likely she didn't expect me to know magecraft or anything. "Well one theory is one that says 'all stories of fiction are stories of the events of another universe', or something like that.