This story is a sequel to Stardust

When Equestria’s newest member of royalty asks for aid to be offered to her friends from abroad, the best and the brightest volunteer to serve. Captain Steel Song of the Dusk Guard are immediately mobilized to help XCOM defend their world from the enemies that besiege them. However, their first joint operation with the humans takes a turn for the worse and they quickly find themselves fighting for their lives against the full force of the monsters that threaten Earth.

(Stardust/Dusk Guard crossover)
(Coverart provided by a friend of Viking ZX!)
(While familiarity with both stories isn’t required, it is recommended)
(Many thanks to Arzoo for pre-reading!)
(All screenshots can be found at XCOM.wikia.com)
(Featured on 3/13/2013. Thanks everyone!)
(Now has it's own section on TVTropes as part of the Stardust series!)

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!)

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!)

Please do check out the Reading List by Lance Omikron to navigate the Amalgam Universe most clearly

A massive war of titanic forces is taking place in the Kaiju's world. However, when two faction's leaders, the current Godzilla and his 'brother' Xenilla duke it out; humanity unleashes its most devastating weapon. Something beyond comprehension occurred and the boundary that divides worlds, if only for the briefest of moments, was torn to shreds. New forms are taken, new bodies assumed. But old hatreds die hard. But how well can hatreds continue in the world of love and tolerance? Especially with its own demons follow it there?

Godzilla Franchise by Toho Company Ltd.
My Little Pony is owned by Hasbro Studios.
This is a non profit fan-work and I claim no ownership on the IP itself.
Story created by Tarbtano
Co-created and Contributed by Faith-Wolff and Skylark8756

HOLY SHEETZU WE GOT FEATURED! THANKS GUYS!
6/27/2014
Now on TV tropes (Thanks Raidrik, VampyGirl; Lance Omikron, Ultimomant, and ZimFan!)

Kaiju Cast:

Godzilla a.k.a Gojira
Xenilla
Mothra
Anguirus
Rodan
Destroyah

[Character copyright of Toho and Daiei Company, artwork property of Matt Frank]

(for any G-fans, Xenilla is the kaiju you may know as Spacegodzilla. I changed the name because I got quirked about typing it repeatedly and am writing the story so it can at least be understood by just an MLP or just a G-fan; and thought it get very confusing that one character's name was just another character's name with an adjective. Also... don't pretend it's the most imaginative name Toho has every made)