This story is a sequel to Stardust

Times are changing for Equestria as Twilight’s return brings with it news of people and cultures from beyond the peaceful world everypony knows. Aid and volunteers are freely offered to help the besieged humans of Earth because every Equestrian knows that’s what good friends do. Unfortunately, making friends can also have the unintended consequence of making enemies.

When the monsters besieging the humans strike at Equestria with a level of brutality not seen in over a thousand years, the cry for help is sent to all the kingdoms of the world. Honored allies step forth to fulfill ancient treaties and oaths. Enemies, old and new, bury their grievances. An alliance never before seen in Equestria will be created to combat the monsters from the void.

And because of these events, a grim but welcome sibling to the XCOM project is born.

(XCOM/FiM Crossover)
(Sequel to Stardust, which I recommend reading before starting this. Fortitude Amicitia and Broken aren't required reading but are supplemental to the storyline)
(Gore tag for blood and violence)
(Alternate Universe tag because of the divergence from canon that Stardust has caused)
(Uses elements of Season 4)
(Coverart produced by the amazing Carnelian!)
(Many thanks to Arzoo, BradTheBrony, Vandenbz and Setokaiva for prereading!)
(As of 03/07/2016, the prereading team consists of Arzoo, BradTheBrony, Noble Cause and Metallusionsismagic!)
(Complete with it's own TVTropes page as part of the Stardust continuity. Could use some updating!)
(Character tags will be added as chapters are added!)
(Featured 5/12/2014! Thanks folks!)
(Possible spoilers in the comments! BEWARE!)

Isolated from her friends and taken prisoner in the middle of a war, Twilight must deal with the very real dangers of being percieved as an enemy as well as the nightmares of her arrival on 'Earth'. Can she overcome her own fears and the fears of her captors? Will the wayward unicorn's assistance be a boon or a curse to the 'humans?' Most importantly, will she ever find her way home?

"In short, it's a story of friendship and plasma rifles, with the emphasis on the friendship. The characters are well written, the XCOM setting is fleshed out very well, and the story is compelling. If you love XCOM, you'll love the story, but even if you've never heard of it, it's more than worth giving the first 3 chapters a read.

There's excellent action later on, but the real strength lies in the collision between the friendly and naive world of Twilight Sparkle and the desperate world of humans fighting a losing war for survival and willing to do anything to turn the tide."

--Arzoo

(XCOM/FiM crossover)
(Cover art commissioned by a friend and created by the magnificent FoxInShadow!)
(Original cover art by the amazing Carnelian can be viewed here!)
(Gore tag for blood and some violence)
(Many thanks to the studius OminousTen, Arzoo, xXFluttershyForeverXx and finally Setokaiva for giving my rambles a once-over)
(Now with it's own TV Tropes page! Get to tropin' folks!)

Rainbows at night. Strange apparitions in the sky. Seismic disturbances. Bizarre rumors.

No doubt about it...there's definitely something strange going on at Canterlot High School.

Twilight Sparkle is determined to get to the bottom of this mystery.

But are the Rainbooms ready to deal with this Twilight Sparkle?

While lounging around Twilight's castle and airing some friendship-related grievances, Discord stumbles across a magic book containing letters from an inter-dimensional pen pal. As it just so happens, this pen pal also had sinister designs for Equestria, but was quashed by the Elements of Harmony. What's more, she's made amends since that day, and she's now Twilight's friendship student. Eager to bond with someone who can relate to him on a personal level and grow into a better draconequus, Discord packs his bags and heads off to the human world with Twilight's semi-blessing. His mission: Befriend Sunset Shimmer.

However, his plan has a bit of a snag. See, Sunset hasn't been keeping up with Equestrian events, and she never got the memo about Discord turning over a new leaf. As such, she believes that his sudden appearance doesn't bode well for Equestria, Canterlot High, or herself. Not only this, but the Sirens are privy to Discord's return as well, and they see this as a golden opportunity to bounce back from their own recent defeat. Well, Adagio does, anyway. Sonata doesn't want to live in a world that makes no sense, and Aria would rather maintain what little dignity she has left by not getting involved (or so she claims).

So while Discord is trying to earn Sunset's trust and show her what a good friend he is now, Adagio is trying to get in on an evil scheme that doesn't exist. And while that is going on, Sonata is appealing to the Rainbooms behind Adagio's back, hoping that they'll make Discord go away. With so much miscommunication thrown into the mix, you just know that hijinks are inevitable. Good thing Aria made popcorn.

Cover art provided by the amazingly talented Neighthirst.

So, I accepted an invitation from a first cousin, once removed. It seemed like a sweet deal at the time, I mean, there were these conventions I wanted to go and he so graciously offered me a place to stay! Alright, so I had to share a room with my brothers, but I had the first convention all for myself! Plenty of cash to spend, and my costume was really easy to make!

Naturally, I spent all of the money that didn't go into my costume on everything that caught my fancy.

I should have left that table alone.

Now? Now... I am not as mad at Celestia as I could have been, as I should have been, all things considered. I can't help but let it be smoke in the wind.

It's in my nature.

And she... she knew there was a chance it would happen.

I'm so sorry, Wind Whistler. It was my fault.

DJSkywalker has been contributing so much, I'm officially adding Dj as a co-author.

This story is a sequel to The Life and Times of an Alchemist Turned Pony

A tower sits in a plain, surrounded by nothing for miles. It is a faithful reconstruction to one that existed before.
Should one have permission to enter, they would find five doors besides the one they used to enter.
Should they ask and be allowed, they could find their way to the bedroom of the master of the tower.
And should they know exactly where to look, they would find his journal, and learn of what happened back in the old world...
The journal of Auric Fulcrum, and it would detail his adventures in Equestria before forming his new life in a new existence...

This story is a sequel to Golden Grace, Headless Headaches

Okay, SO, after stopping Omega and saving Equestria from whatever he had planned, along with Measured from certain death, I kinda, sorta, maybe used up a bit too much of my power.
There's no 'maybe' about it, you did.
And Measured, Twilight, and I are going to do some tests to see how bad it is.
Once you stop flinching at the very mention of Twilight's name.
First things first, though. Someone get me away from Cel, she's gone bananas!

This story is a sequel to Headless, not Heartless

Okay, taking it from the top.
Hi, I'm Auric Fulcrum, also known as Frank DeFontaine. For about 1,500 years, I wasn't alive. I instead inhabited my Dullahan costume as a spirit because of my sword, which also brought me to Equestria. Once I got here, after a few years of back and forth, Sunbutt imprisoned me because of a minor misunderstanding.
I heard that!
You were meant to!
Anyways, once I got out, I learned that the Wise One was coming to this reality, so I did what came natural to me.
I sought out the power of the Golden Sun and used it to defeat him so utterly I would never have to worry about him again.
Problem was, the energies that bound me together and the power of the Sun conflicted, so my armor fell apart. And without the armor, I was unbound, unfocused.
I came to a week later in the same basement I had been imprisoned, in my old body, but with a few...upgrades. Like Alchemy being a Thing I can Do.
Now that I'm alive again, my to-do list is radically different, but no less daunting.
For starters, how am I supposed to stop a mountain from sinking into the earth?!

I was known as Frank DeFontaine. I was going to a Halloween party. I was a pretty intelligent kid, starting my first college term, and decided a little dress-up couldn't hurt.
My buddy Richard got involved, though. And like everything, he took it a bit too far. This time, I didn't say no, though. I really should have.
Next thing I know, we're going all-out on making my Dullahan costume. Because he's my favorite optional boss, and all.
Really shoulda known something was up when that guy behind the counter just so happened to have a sword that fit our specifications perfectly.
Next thing I know, I'm in Equestria. And I'm missing a head.
Sakes, I could use a drink. And a neck.
-----
Featured on 2/19/2014.
I'd like to leave it at "Holy mother of-!" but that doesn't capture what I'm feeling!

What are the chances your favorite pony was secretly a changeling all along?

Yeah, probably about one in one.