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War of Ages by Thunderbird013 reviews
It's been over a year after the alien invasion and the Earth is now threatened by a new extra-terrestrial threat. To combat it, the X-Com project is put back into action, and seeks help across dimensions, and from nearly a dozen different franchises! The writing gets much better after the first chapter, it was written long before the rest.
Crossover - X-Com & X-overs - Rated: T - English - Adventure/Sci-Fi - Chapters: 7 - Words: 22,770 - Reviews: 2 - Favs: 1 - Follows: 3 - Updated: 7/17 - Published: 6/9/2015
The New One's Destiny by SniperInTheHouse reviews
You only get one chance at life right? Marcus learns the hard way that's not the case. Thrown into a different universe with just his wits and hatred for xenos will he tear Shepard's crew apart or be the wild card they need to defeat the collectors, and what's with these dreams haunting Marcus and humans getting along with aliens.
Crossover - X-Com & Mass Effect - Rated: T - English - Adventure/Mystery - Chapters: 13 - Words: 48,959 - Reviews: 42 - Favs: 35 - Follows: 46 - Updated: 7/16 - Published: 11/7/2012 - Shepard (F)
XCOM 2: The Second Contact! by Halofan5695 reviews
After defeating ADVENT, XCOM founded a new government called the Terran Empire, a far-right isolationist government. They even goes as far as to found colonies in the Andromeda galaxy to avoid a second contact. However that did not work, as they make contact with hostile aliens in their colony of Plymouth Rock at the Athena nebula.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi/Tragedy - Chapters: 15 - Words: 100,544 - Reviews: 69 - Favs: 58 - Follows: 71 - Updated: 7/16 - Published: 4/3 - Saren A., Joker, Illusive Man, Shepard (M)
Xcom: Incursion by Drewman784 reviews
Every race thus far has utterly failed to stop the Reapers, always embroiled in pesky politics and wars to take any notice of the coming storm. This time though... this time is different. Can you feel the equally raging storm coming? I can. Two storms will collide, destruction will be everywhere, and I can only hope this time it will be enough.
Crossover - X-Com & Mass Effect - Rated: T - English - Suspense/Adventure - Chapters: 9 - Words: 31,678 - Reviews: 100 - Favs: 173 - Follows: 235 - Updated: 7/13 - Published: 11/28/2015
The Human War by Generatedname reviews
The Citadel Council is a peaceful conglomerate of races, blissfully unaware of the horrors that lurk beyond their space. Humanity, meanwhile, is a race that has fought against these alien horrors ever since they made contact. What will happen when the two societies meet? Will peace follow war? Or is the Citadel Council doomed to fall to humanity? Rewrite of When Civilizations Meet.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi - Chapters: 4 - Words: 47,593 - Reviews: 182 - Favs: 569 - Follows: 789 - Updated: 7/5 - Published: 3/29
Ferris by Jonn Wood reviews
A geek ends up in the XCOM universe. Good News: He's just the Chief Engineer's personal assistant. Bad News: The Chief Engineer is Tony Stark.
Crossover - X-Com & Ironman - Rated: T - English - Sci-Fi/Drama - Chapters: 28 - Words: 106,550 - Reviews: 40 - Favs: 87 - Follows: 100 - Updated: 7/4 - Published: 1/8/2014 - A. E. Stark/Tony
Operation Angry Gods by adipose1913 reviews
When a UFO crashes near Camp Half-Blood, Percy, Annabeth, and the rest of the seven are thrown into a war with creatures even the gods are afraid of. T for mild violence and swearing.
Crossover - X-Com & Percy Jackson and the Olympians - Rated: T - English - Sci-Fi/Adventure - Chapters: 10 - Words: 27,438 - Reviews: 18 - Favs: 17 - Follows: 25 - Updated: 7/3 - Published: 9/26/2015
XCOM: Remnant v2 by Archwar reviews
Remanent has been lost to ADVENT and their alien overlords with Ruby awaking on their capital world, Earth. She joins XCOM in a attempt to find out what happened to her friends as well as her world, but the clock is ticking as the Avatar Project nears completion.
Crossover - X-Com & RWBY - Rated: T - English - Sci-Fi - Chapters: 4 - Words: 14,298 - Reviews: 13 - Favs: 20 - Follows: 35 - Updated: 6/29 - Published: 5/30
Psi Effect by Cap'n Chryssalid reviews
A fun-loving asari mercenary finds herself a little in over her head when she ends up abducted by terrifying aliens from beyond the galactic frontier. These asari-like creatures call themselves 'humans.' They seem to be secretly nosing about on the borders of known space, acting through proxies, conducting covert operations, and they've got a deal for an enterprising asari...
Crossover - X-Com & Mass Effect - Rated: T - English - Humor/Sci-Fi - Chapters: 30 - Words: 285,976 - Reviews: 999 - Favs: 2,313 - Follows: 2,730 - Updated: 6/16 - Published: 7/19/2014 - U. Wrex, Daro'Xen, Shepard (F), OC
I Watch, I Believe by Nenshou Yuuki Medic of Aincrad reviews
Humanity has survived the Ethereal war and begun to spread it's wings across the stars, constantly vigilant against the threat that the Ethereal's warned them of, but there is already an established order to the galaxy, will they co-exist or will they have to raise their weapons once more. Whatever the case is, X-COM is ready. Vigilo Confido.
Crossover - X-Com & Mass Effect - Rated: T - English - Adventure - Chapters: 1 - Words: 1,371 - Reviews: 8 - Favs: 27 - Follows: 49 - Published: 6/10
The Avenger Through The Ides Of Space by Lo and behold my fiction reviews
A mission went terribly wrong, a traitor, a mole, had given ADVENT backdoor access to our operations. I've seen snake women, Beserkers, and those damned Sectoids, but this world..it's different, green and full of life, like Earth was, and these creatures. Crystal Gems? That tops it all, they may be able to outsmart us, but let's see if they can outsmart a high-powered Gauss rifle
Crossover - X-Com & Steven Universe - Rated: T - English - Sci-Fi/Adventure - Chapters: 7 - Words: 7,833 - Reviews: 5 - Favs: 5 - Follows: 6 - Updated: 6/1 - Published: 5/22
XCOM: Remnant by Archwar reviews
As the Grimm attack Vale, a new force suddenly appeared and invades. Ruby Rose attempted to defeat the invaders and succeeds to an extent, but gets knocked out by a lucky blow. She is then taken prisoner and imprisoned on ADVENT's earth. Now with limited support, she must find out what happened to Remnant before the Avatar Project is completed.
Crossover - X-Com & RWBY - Rated: T - English - Chapters: 6 - Words: 22,088 - Reviews: 33 - Favs: 35 - Follows: 51 - Updated: 5/30 - Published: 2/5
Welcome to Remnant by kinggaben reviews
What started out as a smash and grab mission, turns into a whole new adventure for a young Australian grenadier. After ending up in a different world filled with blood thirsty monsters and terrorists, he must now, instead of liberating the planet, he must now protect it with his life. (rest of summary inside) PAIRINGS UNDECIDED, MAY MAKE POLE LATER! (Cover image is my OC)
Crossover - X-Com & RWBY - Rated: T - English - Adventure/Sci-Fi - Chapters: 4 - Words: 6,012 - Reviews: 2 - Favs: 8 - Follows: 21 - Updated: 5/20 - Published: 5/6 - Ozpin, OC, Team RWBY, Team JNPR
Zerg-COM by Summer Gambit reviews
A new kind of alien has shown up on earth and their numbers are massive. Is X-COM's fight to take back the earth in the end in vain? Or did X-COM just got a very powerful ally?
Crossover - StarCraft & X-Com - Rated: T - English - Sci-Fi - Chapters: 2 - Words: 7,475 - Reviews: 9 - Favs: 22 - Follows: 42 - Updated: 4/8 - Published: 3/22 - Sarah K., Zerg
When Civilizations Meet by Generatedname reviews
The Ethereals, the Aquatoids, the Micronoids. Humanity has faced them all, and come out stronger. The Humans have left their world, exploring the stars, their technology built on Alien corpses. How will they react when they meet a peaceful society, one that is both advanced and primitive? ABANDONED, REWRITE IS UP UNDER THE TITLE 'THE HUMAN WAR!
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi/Adventure - Chapters: 17 - Words: 52,325 - Reviews: 323 - Favs: 691 - Follows: 825 - Updated: 3/29 - Published: 5/11/2014 - OC
XCOM: Mass Effect by Potatofanfiction reviews
Humanity has successfully destroyed ADVENT and the Elders. As humanity rejoices, the newly formed Union looks to the stars. It is unavoidable, then, that the Union, newly born from the embers of conflict would eventually meet with the Citadel.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi - Chapters: 2 - Words: 5,959 - Reviews: 41 - Favs: 118 - Follows: 187 - Updated: 3/16 - Published: 3/10
XCOM: Viral Offense (Old) by Fw00sh reviews
Seven years after the infection of Manhattan, Mercer is bored. When a new threat to the world arises along with a whole new team to combat it, Mercer definitely isn't bored anymore. One thing is for sure, the aliens are in for a nasty surprise. Rated for language and violence. (Old: New Version in Progress)
Crossover - X-Com & Prototype - Rated: T - English - Horror/Sci-Fi - Chapters: 7 - Words: 9,909 - Reviews: 62 - Favs: 202 - Follows: 247 - Updated: 3/9 - Published: 10/24/2012 - Alex M./Zeus - Complete
XCOM: Viral Offense by Fw00sh reviews
In the midst of the war to defend Earth, XCOM finds themselves looking for any possible edge against the invaders. Will a strange sample held by a hostile organization hold the key? Who is Alex Mercer? Whatever the answers, the aliens are certainly in for a nasty surprise. Rated for language and violence.
Crossover - X-Com & Prototype - Rated: T - English - Adventure/Horror - Chapters: 1 - Words: 1,684 - Reviews: 15 - Favs: 114 - Follows: 155 - Published: 3/9
Garfield seeks vengeance on the Aliens for their prior misdoings by Loodlelood
Years ago our hero was promised lasagna, yet he had received only betrayal. Join Garfield as he travels on a journey to help both sides of this conflict come to terms with one another. Garfield will travel the world, spreading love and peace to the population of earth. Also remember kids, abhore the mutant and purge the xenos. The filth of the Aliens is not to be tolerated.
Crossover - X-Com & Garfield - Rated: T - English - Hurt/Comfort/Friendship - Chapters: 1 - Words: 2,832 - Favs: 1 - Published: 3/7
XCOM: Impact by timedraven117 reviews
The Inusannon, and the Protheans, failed. The Cycle continues. One Inusannon breaks. Another teaches. And the youngest, fights. Humanity will take a central role in leading the charge of the future. The Reaper's days are numbered. Indeed, it is the beginning of the end. A war that will shake the galaxy and will never be seen again.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi/Supernatural - Chapters: 4 - Words: 19,749 - Reviews: 29 - Favs: 72 - Follows: 118 - Updated: 2/20 - Published: 11/10/2015
X-Com Into Darkness by deathwing17 reviews
After an information gathering mission in China, The leaders of X-Com learn that something strange is going on in Japan. They send a team in to investigate only for them to find something more disturbing than they originally feared.
Crossover - X-Com & Brynhildr in the Darkness/極黒のブリュンヒルデ - Rated: T - English - Sci-Fi/Horror - Chapters: 7 - Words: 40,428 - Reviews: 17 - Favs: 33 - Follows: 38 - Updated: 1/28 - Published: 8/12/2014
Family Reunion by Afalstein
In the wake of the Secret Invasion of 1962, two estranged family members meet at a diner. One's on her way out of the espionage business, the other has just gotten dragged back in, but they're both very interested in the future.
Crossover - X-Com & Agent Carter - Rated: K+ - English - Friendship - Chapters: 1 - Words: 1,219 - Favs: 1 - Published: 1/18 - P. Carter - Complete
La locura de haruhi suzumiya by Ministro Frollo reviews
imagina que el mundo de haruhi un dia se vuelve un reverendo desma... con una guerra entre alienigenas y la humanidad esta es la historia, disfrutala!
Crossover - Haruhi Suzumiya series & X-Com - Rated: T - Spanish - Adventure/Sci-Fi - Chapters: 1 - Words: 3,058 - Reviews: 1 - Published: 1/17
Vigilance in the Shadows by tatantyler reviews
The Witches are, and have always been, humanity's counter to the Neuroi. But when a new threat that surpasses even the power of the Witches rises alongside the ongoing Neuroi invasion, one group stands against the coming storm. Vigilant and confident, they are the 115th Experimental Combat Unit: X-COM.
Crossover - X-Com & Strike Witches - Rated: T - English - Sci-Fi/Drama - Chapters: 6 - Words: 33,265 - Reviews: 12 - Favs: 18 - Follows: 24 - Updated: 12/30/2015 - Published: 11/24/2015 - Yoshika M.
Of Psychics and Flying Chthulu-ships by Dr1ft3r0I reviews
The Volunteer ended the war. Now he and the best of X-Com are stuck in a world that they don't know, surrounded by aliens that may or may not want to kill them all. Oh, and there's a giant metal cuttlefish in the sky. Starts post X-COM: EU, beginning of ME1. Not CRACK!
Crossover - X-Com & Mass Effect - Rated: T - English - Adventure/Sci-Fi - Chapters: 5 - Words: 20,119 - Reviews: 40 - Favs: 127 - Follows: 241 - Updated: 12/26/2015 - Published: 4/29/2015 - [Shepard (F), Garrus V.]
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