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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: 4 - Words: 14,349 - Reviews: 26 - Favs: 62 - Follows: 123 - Updated: 7/3 - Published: 4/29 - Shepard (F)
Council's notes on Humanity by 5 Coloured Walker reviews
This is the Citadel Codex as it applies to Humans in the [TBD] world, who's current stories include: Busy Stars This however is not the codex of general things however, not is it human's documentation on aliens.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi - Chapters: 6 - Words: 5,906 - Reviews: 1 - Favs: 22 - Follows: 22 - Updated: 7/2 - Published: 2/11
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: 24 - Words: 94,070 - Reviews: 31 - Favs: 63 - Follows: 83 - Updated: 6/30 - Published: 1/8/2014 - A. E. Stark/Tony
Smoke on the Water by P.H. Wise reviews
Centuries after the Ethereal war, after humanity discovered a galaxy filled with alien life, after the defeat of Sovereign, the abductions have begun again. This time, entire human colonies are disappearing. And a reborn Commander Shepard and the long-thought defunct Extraterrestrial Combat Unit may be the only thing standing between humanity and extinction... (XCOM/Mass Effect)
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi - Chapters: 7 - Words: 53,739 - Reviews: 35 - Favs: 123 - Follows: 185 - Updated: 6/27 - Published: 7/19/2014 - Shepard (F), Liara T'Soni, Miranda L.
Avatar:The New Teammate by EliteOp reviews
The Psion finds himself fighting a whole new war after the destruction of the Temple ship. His team, gone, he has to make new friends and figure out the truth before it is too late.
Crossover - X-Com & Avatar: Last Airbender - Rated: T - English - Romance/Adventure - Chapters: 2 - Words: 1,963 - Reviews: 1 - Favs: 1 - Updated: 6/24 - Published: 6/18 - Aang, Sokka, Katara, Toph
Re-activation by skyfire777 reviews
After the war, XCOM was reduced to conspiracy theories and urban myths. They did not exist in any shape or form. But they were far from gone. Now, after 50 years of rebuilding, humanity faces yet another threat. Now, after 50 years of preparations, XCOM stands ready to face that threat. Covert!XCOM. Rating subject to change
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi/Suspense - Chapters: 4 - Words: 5,775 - Reviews: 14 - Favs: 57 - Follows: 118 - Updated: 6/23 - Published: 4/18
RWBY:Psion Unleashed by EliteOp reviews
The Volunteer was considered KIA aboard the mothership, his lifesigns disappearing. Noone knows where he went but him. He needs to set up, find allies and enjoy his new life while he can, as dark things are coming.
Crossover - X-Com & RWBY - Rated: T - English - Romance/Humor - Chapters: 9 - Words: 11,031 - Reviews: 5 - Favs: 6 - Follows: 11 - Updated: 6/23 - Published: 6/9
Sunrider:Ceran Liberators by EliteOp
The war continues in the neutral rim, as PACT is being pushed back by the Sunrider and the Alliance, a new ship appears with a whole new crew and a strange story. (Continuation of Sunrider:Shadow of Noble)
Crossover - X-Com & Sunrider - Rated: T - English - Romance/Sci-Fi - Chapters: 1 - Words: 810 - Favs: 1 - Published: 6/19
Mass Effect: X-Com Theory: Project Shanxi by timedraven117 reviews
It has been over a century since the Ethereal Invasion and the Equis First Contact War. Humanity has learned to accept their former foes, and their former victims. But the threat has always remained, "The greater foe" promised by the UberEthereal. Now it is the year 2157, near the Shaanxi system the Relay War shall begin with a galactic order that has stood for over 2,000 years.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi/Supernatural - Chapters: 9 - Words: 51,124 - Reviews: 39 - Favs: 129 - Follows: 156 - Updated: 6/16 - Published: 5/8 - Admiral Hackett, Councilor Tevos, Primarch Adrien Victus
War of Ages by Thunderbird013
A crossover between nearly a dozen different franchises! It's been over a year after the alien invasion and the Earth is now threatened by a new extra-terrestrial threat. To combat them, the X-Com project is put back into action and seeks help across dimensions. Again, not just a crossover with Metroid. I could put two franchises that were being crossed over.
Crossover - X-Com & Metroid - Rated: T - English - Adventure/Sci-Fi - Chapters: 1 - Words: 2,938 - Published: 6/9
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: 16 - Words: 156,090 - Reviews: 508 - Favs: 1,481 - Follows: 1,783 - Updated: 5/29 - Published: 7/19/2014 - U. Wrex, Daro'Xen, Shepard (F), OC
Vigil by Peptuck reviews
Mankind has survived its crucible, and while scarred and changed by the Ethereals, they advance into the cosmos. The galaxy beyond is a place of wonder and terror, of wealth and strife. Amid the threats and opportunities, both within and without, XCOM remains vigilant. Mass Effect/XCOM/Eclipse Phase/FEAR fusion.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi/Adventure - Chapters: 14 - Words: 137,257 - Reviews: 355 - Favs: 636 - Follows: 703 - Updated: 5/12 - Published: 9/2/2014
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: 5 - Words: 28,311 - Reviews: 13 - Favs: 21 - Follows: 26 - Updated: 5/3 - Published: 8/12/2014
X-com: The Kisaragi squad remake by BlackThief12 reviews
Is a remake dude. Check the god damn story for the user of Library of the damn.
Crossover - X-Com & Corpse Party - Rated: T - English - Sci-Fi/Supernatural - Chapters: 1 - Words: 1,523 - Reviews: 1 - Published: 4/16
Dust and Psionics by Malcho1234 reviews
[DISCONTINUED. Look for Vigilant for the rewrite.] Tossed in a new world... One full of strange enemies and even stranger humans... And yet, there is one thing that remains the same: Humanity is in danger. And Christopher Redmond had sworn to protect Humanity... Rated T because of XCOM
Crossover - X-Com & RWBY - Rated: T - English - Fantasy/Sci-Fi - Chapters: 6 - Words: 21,704 - Reviews: 53 - Favs: 99 - Follows: 115 - Updated: 4/15 - Published: 10/11/2014 - Ruby Rose, Weiss Schnee, Yang Xiao Long, OC - Complete
Vigilant by Malcho1234 reviews
He had sworn to protect Humanity... It was his mission. His purpose. Not even the high odds of his death managed to turn him away... And even though he is sent to another world Christopher Redmond will continue fighting and protecting Humanity. For that is what a soldier of XCOM does. Rewrite of Dust and Psionics.
Crossover - X-Com & RWBY - Rated: T - English - Sci-Fi/Adventure - Chapters: 1 - Words: 1,979 - Reviews: 11 - Favs: 52 - Follows: 83 - Published: 4/15 - Weiss Schnee, OC, Penny, General James Ironwood
Dehumanization by DasCheesenborgir reviews
He always had been more machine than man.
Crossover - Resident Evil & X-Com - Rated: T - English - Chapters: 1 - Words: 1,597 - Reviews: 1 - Follows: 1 - Published: 4/3 - HUNK
The Wakfu is out there by du911
Nox may have failed...but his legacy lives on...to completely screw over two universes! Inspired by Hotpoint and Psykotic Addiction!
Crossover - X-Com & Wakfu - Rated: T - English - Sci-Fi/Adventure - Chapters: 1 - Words: 433 - Published: 3/29
Fallout: Alien Activity by Sheepking
In which the apocalypse was the result of an alien invasion. Labelled In-Progress in case I ever feel like picking this back up.
Crossover - X-Com & Fallout - Rated: T - English - Chapters: 1 - Words: 288 - Published: 3/27
Adapt and Survive by nivlac reviews
It has been two weeks since Rolf Anderson sacrificed his life to save the earth, and during his funeral, a mysterious cloaked man took them and their base from the earth that they worked so hard to save. The base was put on a new, more hostile version of earth, full of mutants, slavers, radiation, and power armored soldiers with laser and plasma technology on par with their own.
Crossover - X-Com & Fallout - Rated: T - English - Tragedy/Mystery - Chapters: 2 - Words: 7,086 - Reviews: 13 - Favs: 18 - Follows: 24 - Updated: 3/7 - Published: 11/27/2014 - Lone Wanderer, Elder Lyons, Fawkes, Colonel Autumn
I Am Watchful I Am Necessary by TheConstellation reviews
Decades have past since the Ethereals threat was defeated and humanity has emerged united and stronger than ever for the conflict it faced. Now after discovering the Prothean Archives on Mars, humanity is about to end up on a much larger stage than it ever expected to play on when yet another alien threat comes knocking. And again, X-COM stands ready to fight. Vigilo Confido.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi - Chapters: 9 - Words: 18,569 - Reviews: 359 - Favs: 709 - Follows: 983 - Updated: 2/25 - Published: 9/30/2013 - Admiral Hackett
Aleandrea's Alien Primer - Combined and Condensed Edition by 5 Coloured Walker reviews
Alien's aren't just people with rubber faces and funny hats.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi - Chapters: 2 - Words: 2,189 - Reviews: 3 - Favs: 3 - Follows: 4 - Published: 2/18
X-com percy jackson crossover challenge by themarineguy
This is really just a challenge
Crossover - X-Com & Percy Jackson and the Olympians - Rated: K - English - Chapters: 1 - Words: 222 - Published: 1/31
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: 6 - Words: 17,532 - Reviews: 44 - Favs: 87 - Follows: 83 - Updated: 1/5 - Published: 8/10/2014 - Complete
X-COM: Silence Within by jak3combat reviews
My name is David Zalian, used to be a Lance Corporal in the USMC. April 1st, 2015, we had official first contact. It... went rather poorly, and I ended up recruited by a group of people only known as X-COM. I have a few suspicions about my new Commander, but I have more pressing things to deal with.
Crossover - X-Com & My Little Pony - Rated: T - English - Sci-Fi - Chapters: 1 - Words: 1,736 - Reviews: 4 - Favs: 8 - Follows: 12 - Published: 12/3/2014
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