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United Species Federation Codex by ZawrotekPL reviews
Codex for United Species Federation Crossovers. Contains all valuable information about United Species Federation including timeline, army, and races.
Crossover - X-Com & Game X-overs - Rated: T - English - Sci-Fi - Chapters: 1 - Words: 2,543 - Reviews: 1 - Published: 4/20 - Complete
NERVous Breakdown by Tabac Iberez reviews
With the Second Impact stilled in the cradle, Earth would be in better in shape were it not for the ravages of the Aliens. As SEELE lie in wait, the Commander must act as the world's faith in his organization of XCOM is called to absorb the aborted NERV project and stand ready to defend Earth again with weapons and tools more foreign than any Alien Artifact: the EVA units.
Crossover - Evangelion & X-Com - Rated: T - English - Chapters: 13 - Words: 27,315 - Reviews: 2 - Favs: 19 - Follows: 17 - Updated: 4/17 - Published: 2/1
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: 10 - Words: 36,193 - Reviews: 2 - Favs: 1 - Follows: 3 - Updated: 4/13 - Published: 6/9/2015
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: 33 - Words: 122,646 - Reviews: 41 - Favs: 95 - Follows: 111 - Updated: 4/10 - Published: 1/8/2014 - A. E. Stark/Tony, OC
XCOM: The Resurgance by Halofan5695 reviews
When a sarcastic, rich, genius, loses his parents to slavers. He goes out in the galaxy for revenge on that Batarian. All the while, rebuilding an old organization, and discovering something worse than Batarian slavers.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi/Drama - Chapters: 1 - Words: 4,357 - Reviews: 3 - Favs: 15 - Follows: 16 - Published: 3/14 - OC, Liara T'Soni
X-COM: The Glorious Ones Revealed by maringarcias
Dan needs the help of eight historical figures to save Elisa from the Nuclear-Beth.; Warning: Nuclear Gandhi EXPOSED!; Nuclear-Beth is a parody to memetic Nuclear Gandhi which has his obsessive nuclear warmongering, in stark contrast to the pacifist reputation of the real life counterpart from Civilization franchises.; Disclaimer: No one owns Civilization but Sid Meier!
Crossover - X-Com & Civilization Series - Rated: T - English - Sci-Fi/Adventure - Chapters: 2 - Words: 2,983 - Updated: 3/6 - Published: 2/11 - Bradford, OC, Ghandi, Isabella - Complete
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. Side story: Incursion: Alliance Effect
Crossover - X-Com & Mass Effect - Rated: T - English - Suspense/Adventure - Chapters: 10 - Words: 37,989 - Reviews: 119 - Favs: 231 - Follows: 307 - Updated: 3/2 - Published: 11/28/2015
Reparations by Gregg Landsman reviews
One hundred and seventy years after the Temple Ship, humanity has spread out among the stars and found to their surprise that the aliens they thought of as monsters and conquerors were saints and jerks just like everyone else. That and as it turns out the Ethereals were really, really sorry.
Crossover - X-Com & Mass Effect - Rated: T - English - Adventure/Humor - Chapters: 3 - Words: 25,987 - Reviews: 50 - Favs: 141 - Follows: 228 - Updated: 2/11 - Published: 1/24
XCOM: Asset Assault by Hoxtilicious12 reviews
After the destruction of ADVENT, Humanity founded the Terran Republic. All of humanity was enjoying economic prosperity and improved freedom over their previous government. But one of their colonies gets contacted by the asari. Which leads to the events that are about to unfold before your very eyes.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi - Chapters: 2 - Words: 10,417 - Reviews: 16 - Favs: 24 - Follows: 33 - Updated: 2/5 - Published: 1/29 - Liara T'Soni, Illusive Man, OC
Ordo XCom: A Warhammer 40K - XCOM 2 Crossover by JinterIsComing reviews
An investigation into a cursed world. An Inquisitor clinging to her faith. A Deathwatch Team with a mysterious purpose. An unexpected journey to another universe, where the last hope of humanity struggles against the xenos scum that have subjugated Earth.
Crossover - X-Com & Warhammer - Rated: T - English - Adventure - Chapters: 4 - Words: 5,462 - Reviews: 7 - Favs: 28 - Follows: 41 - Updated: 1/31 - Published: 10/19/2016
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: 9 - Words: 50,331 - Reviews: 21 - Favs: 37 - Follows: 43 - Updated: 1/21 - Published: 8/12/2014
Against All Tyrants by swimmingcop reviews
In their desperation to stamp out the last of humanity's resistance, the ADVENT Coalition turns to unconventional measures to end the war. They just didn't know it was going to be so effective.
Crossover - X-Com & Fallout - Rated: T - English - Sci-Fi/Adventure - Chapters: 4 - Words: 15,307 - Reviews: 5 - Favs: 18 - Follows: 25 - Updated: 1/12 - Published: 1/1 - Courier
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: 6 - Words: 67,803 - Reviews: 295 - Favs: 864 - Follows: 1,203 - Updated: 1/9 - Published: 3/29/2016
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: 6 - Words: 32,013 - Reviews: 32 - Favs: 95 - Follows: 147 - Updated: 1/2 - Published: 11/10/2015
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: 17 - Words: 63,083 - Reviews: 50 - Favs: 46 - Follows: 65 - Updated: 12/28/2016 - Published: 11/7/2012 - Shepard (F)
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: 31 - Words: 292,418 - Reviews: 1074 - Favs: 2,622 - Follows: 3,071 - Updated: 12/26/2016 - Published: 7/19/2014 - U. Wrex, Daro'Xen, Shepard (F), OC
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: 6 - Words: 26,036 - Reviews: 47 - Favs: 153 - Follows: 272 - Updated: 12/25/2016 - Published: 4/29/2015 - [Shepard (F), Garrus V.]
Incursion: Alliance Effect by Drewman784 reviews
We all remember the First Contact War, the brief but devastating contact war between the Species Alliance and the Turian Hierarchy. But now the war is over and diplomatic relations are being established as we speak. So the question is, what happens now after the war is over? *Side-story to Xcom: Incursion*
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi/Suspense - Chapters: 3 - Words: 8,161 - Reviews: 3 - Favs: 48 - Follows: 54 - Updated: 12/20/2016 - Published: 10/2/2016
Hunting Aliens by Zerodone reviews
Samus should have known better, replacing her destroyed engine with one built by the Pirates. Their so called engineers were incompetent enough to build an engine that lets her travel through dimensions! Of course, her ship didn't have a navigation device for something like that and for the moment she's stuck in an alternate earth that's being attacked by aliens.
Crossover - X-Com & Metroid - Rated: T - English - Sci-Fi - Chapters: 1 - Words: 5,477 - Reviews: 3 - Favs: 12 - Follows: 23 - Published: 11/19/2016 - Samus A.
XCOM: Remnant v2 by Archwar reviews
Remnant 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: 6 - Words: 22,983 - Reviews: 18 - Favs: 31 - Follows: 48 - Updated: 10/27/2016 - Published: 5/30/2016
Gamer X-Commander by Angel of light darkness reviews
An experimental One Shot. Please read Author's Note at the end for an questions you may have
Crossover - X-overs & X-Com - Rated: T - English - Humor - Chapters: 1 - Words: 3,920 - Reviews: 4 - Favs: 12 - Follows: 11 - Published: 10/18/2016 - Complete
X-Com: Contact Wars by Zanji of clan okami reviews
First contact it was supposed to be great moment in history, but it lead to only war. What followed was the beginning of a clash between civilizations that would shake the very foundations of the galaxy. (A little crossover that's type has never been done before) T for now
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi - Chapters: 1 - Words: 643 - Reviews: 1 - Favs: 6 - Follows: 6 - Published: 9/30/2016
Shinobi Autopsy by fyleisch reviews
An experiment gone awry, an explosion, strange surroundings. A group of XCOM personnel are warped into an unfamiliar region, filled by people with abilities which beggar belief. There are no signposts on this road into the dark future of humanity, but with determination and ruthless efficiency there may be ways to create light. An XCOM-Naruto crossover set in the Naruto world.
Crossover - X-Com & Naruto - Rated: T - English - Drama/Sci-Fi - Chapters: 5 - Words: 34,645 - Reviews: 9 - Favs: 31 - Follows: 33 - Updated: 9/27/2016 - Published: 9/17/2016
XCOM: Sonic Boom by LegoKid343
After falling into Lyric's trap, Sonic and his posse are sent to another world in the midst of an alien invasion. But will the XCOM and the Council treat them as friend or foe? (Contains SonAmy)
Crossover - Sonic the Hedgehog & X-Com - Rated: T - English - Sci-Fi/Romance - Chapters: 1 - Words: 1,338 - Favs: 2 - Follows: 2 - Published: 9/26/2016 - Sonic, Amy
XCOM: Enemy Monstrous by Malcho1234 reviews
[PENDING REWRITE] It was over... XCOM defeated the Enemy from the unknown reaches of Space. They eliminated the enemy within... But threats for Humanity still exist, and they are closer than ever, living amongst us... It is time for X-COM's youngest Operative to face the Enemy Monstrous... Rated T because of XCOM.
Crossover - X-Com & Rosario + Vampire - Rated: T - English - Supernatural/Sci-Fi - Chapters: 3 - Words: 17,137 - Reviews: 53 - Favs: 99 - Follows: 98 - Updated: 9/18/2016 - Published: 8/10/2014 - Complete
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