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The XCOM Effect by Havocfrost reviews
2183: Humanity has survived second contact, but now Eden Prime burns and the ancient boogeymen of Earth's past are set to destroy the fragile place Humanity has earned. Beset on all sides by indifferent allies and hostile alien races, only one man can bring the galaxy back from the brink and unite the disparate species against the real foe threatening them all.
Crossover - X-Com & Mass Effect - Rated: T - English - Adventure/Sci-Fi - Chapters: 3 - Words: 23,152 - Reviews: 23 - Favs: 61 - Follows: 84 - Updated: 4/8 - Published: 3/26 - Saren A., Shepard (M)
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: 9 - Words: 28,512 - Reviews: 4 - Favs: 23 - Follows: 37 - Updated: 4/3 - Published: 1/8 - A. E. Stark/Tony
The Magpies by Knight in Blackest Armor reviews
With the technologies of several alien races at its disposal, humanity had undergone a technological revolution. It advanced at such a rapid pace, far exceeding many expectations. Soon however, the humans learned that they shared their galaxy with yet another group of sentient alien life, but to mankind's horror and confusion, these aliens were not the sort they expected at all.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi - Chapters: 2 - Words: 23,288 - Reviews: 48 - Favs: 152 - Follows: 243 - Updated: 3/25 - Published: 3/20 - Shepard (M)
XCOM: To Boldly Go by JohnLocke94 reviews
First attempt at XCOM: Enemy Unknown crossover fic with Star Trek... hoping to carry on for quite a while down the line. As a general guideline, I like to either write horribly dark and depressing thoughts on why humans are such awful things, or just embrace it and go, Humanity! F**k Yeah! This is the second type of story.
Crossover - StarTrek: Other & X-Com - Rated: T - English - Sci-Fi/Adventure - Chapters: 25 - Words: 50,042 - Reviews: 57 - Favs: 37 - Follows: 45 - Updated: 3/15 - Published: 5/2/2013
Extradimensional Assistance by President John Henry Eden reviews
Commander Shepard found himself in command of six alien hunters from a neighboring parallel universe. Now, he has the new responsibility of trying to keep the XCOM operatives in his squad from tearing the Normandy crew apart with either rampant xenophobia, or just by plain old poor communication skills. Starts from ME2's Freedom's Progress. Ends in Collector Base? Not necessarily.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi/Friendship - Chapters: 4 - Words: 47,038 - Reviews: 29 - Favs: 65 - Follows: 78 - Updated: 3/11 - Published: 2/23 - Garrus V., Tali'Zorah, Shepard (M)
XCOM Mass Effect Crossover challenge by superezra reviews
i'm sary the original challenge got taken down because of some personal info if you read this is me then you now wot i'm talking about anyway package sacrifices him self to save the temple ship and to give the aliens back their freedom new earth government xcom renamed aliens (organic and sinthatic) gain equal wrights advans throw the threw the stars warp drives super careers bla
Crossover - X-Com & Mass Effect - Rated: T - English - Adventure/Sci-Fi - Chapters: 3 - Words: 830 - Reviews: 11 - Favs: 2 - Follows: 2 - Updated: 1/25 - Published: 10/10/2013
Operation Broken Sun by ZenIaidoka reviews
(Rewrriten!) Two Xcom teams have been deployed to Japan to prep for an incoming terror attack on Tokonosu City. Little do realize that they are not the only ones fighting to survive in a city under siege. What happens when these teams meet up with an unruly band of teenagers to continue their fight? May move up to M
Crossover - X-Com & Highschool of the Dead - Rated: T - English - Adventure - Chapters: 5 - Words: 10,760 - Reviews: 13 - Favs: 16 - Follows: 16 - Updated: 1/20 - Published: 10/6/2013
The Excommunication Project: Enemy Unknown by Phalanx reviews
Diablo might have been sealed within the Black Soulstone, but the Prime Evils were not the only ones interested in subverting humanity for their own purposes. Peace is shattered by an invasion of strange, alien demons, and a desperate Angiris Council appoints the Nephalem to lead the Excommunication Project: Sanctuary's first and only last line of defense against the Ethereal Ones.
Crossover - Diablo & X-Com - Rated: T - English - Sci-Fi/Fantasy - Chapters: 2 - Words: 2,779 - Reviews: 3 - Favs: 1 - Follows: 5 - Updated: 1/20 - Published: 12/28/2013 - Demon Hunter, Tyrael
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: 6 - Words: 12,693 - Reviews: 222 - Favs: 412 - Follows: 577 - Updated: 12/20/2013 - Published: 9/30/2013 - Admiral Hackett
X-COM Ponies by sneaky breeze reviews
Humanity is under attack by a violent alien empire that enslaves any race that dares to defy them. Mankind unites to form X-COM an international combat unit dedicated to defending the Earth from alien incursion. But Discord, the god of chaos, finds this war of ours interesting and sends us aid so that the entire empire can be thrown into chaos.
Crossover - X-Com & My Little Pony - Rated: T - English - Sci-Fi/Friendship - Chapters: 22 - Words: 95,457 - Reviews: 12 - Favs: 16 - Follows: 16 - Updated: 11/30/2013 - Published: 3/26/2013 - Trixie, Ditzy Doo, Discord
X-Com, a new threat by Deathtroll reviews
set in the X-Com universe, at 2100 hours GMT, a scientific expedition went dark, at 0100 Hours our colony on Shanxi went dark, sending an hostile aliens SOS, this is what happened after, please note I have not played ME1.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi - Chapters: 2 - Words: 1,329 - Reviews: 2 - Favs: 24 - Follows: 28 - Published: 11/22/2013 - Shepard (F)
El Voluntario by Leviathan2.0 reviews
Fue el Salvador de la Humanidad, pero ya nadie se acuerda de él ni de la guerra que lucho ni de su nombre. Pero él aún esta alli, vigilando. El no fue solo el Voluntario. Él fue mucho más.
Crossover - X-Com & Warhammer - Rated: K - Spanish - Sci-Fi - Chapters: 1 - Words: 1,013 - Reviews: 2 - Favs: 3 - Follows: 1 - Published: 10/20/2013 - Complete
X-COM: Enemy Unnatural by sun tzu1 reviews
Short X-COM/Saga of Soul crossover. Less than a year after the battle of the Temple Ship, X-COM has to face an entirely different kind of alien threat.
Crossover - Misc. Books & X-Com - Rated: K+ - English - Sci-Fi/Fantasy - Chapters: 1 - Words: 3,285 - Reviews: 1 - Favs: 3 - Follows: 1 - Published: 9/22/2013 - Complete
XCOM: Second Contact by Agayek reviews
With the destruction of the Temple Ship humanity knew peace. XCOM never forgot their motto however, 'always vigilant, always reliable'
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi/Adventure - Chapters: 26 - Words: 294,105 - Reviews: 924 - Favs: 1,443 - Follows: 1,526 - Updated: 9/15/2013 - Published: 1/1/2013
A Mind of Madness by idrawedyouaduck
SPOILER WARNING: Does contain plot spoilers. An alternate version of the Joker's interrogation in the film The Dark Knight as performed by a psionic commando from XCOM: Enemy Unknown.
Crossover - X-Com & Batman Begins/Dark Knight - Rated: T - English - Suspense - Chapters: 1 - Words: 3,411 - Favs: 1 - Published: 7/27/2013 - J. Gordon, Bruce W./Batman, Joker - Complete
Across Time and Space, There's Always Earth by Wanderer D reviews
A new energy signal discovered in the middle of the Reaper invasion might be just what Shepard needs... or perhaps it might doom them all. Despite ending up in unexpected places, Shepard knows what she aims to protect, because, even across Time and Space... there's always Earth.
Crossover - X-Com & Mass Effect - Rated: T - English - Adventure/Sci-Fi - Chapters: 1 - Words: 4,039 - Reviews: 15 - Favs: 42 - Follows: 75 - Published: 6/13/2013 - Shepard (F), Garrus V., Liara T'Soni, U. Wrex
The Volunteer by Primordial Soul reviews
A hero's duty never ends. A hero's journey never ceases. A hero never dies. If energy cannot be destroyed, then heroes never fall. They only move on. The Volunteer follows this creed. And in this new universe, the Volunteer will do what she does best. For she is XCOM. Always vigilant. Always reliable. Post ME1. Volunteer/Liara. ON-HOLD
Crossover - X-Com & Mass Effect - Rated: T - English - Chapters: 1 - Words: 3,947 - Reviews: 21 - Favs: 49 - Follows: 80 - Published: 3/30/2013 - Liara T'Soni, Nyreen K.
Strike-COM by Vn70072 reviews
An unexpected arrival during an XCOM operation puts the project in contact with three beings of unusual and extraordinary power...
Crossover - X-Com & Strike Witches - Rated: T - English - Sci-Fi - Chapters: 6 - Words: 25,409 - Reviews: 13 - Favs: 22 - Follows: 31 - Updated: 3/22/2013 - Published: 12/11/2012
The war that never ends by Masterblader158 reviews
Mankind survived against all odds and now they must do it again but this time much much harder and bigger. (Will fit in Marauder Shields at an appropriate time in the story) need reviews to help me improve and for suggestions.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi/Adventure - Chapters: 2 - Words: 1,615 - Reviews: 2 - Favs: 17 - Follows: 23 - Updated: 2/1/2013 - Published: 1/25/2013 - Marauder Shields
Xcom: Enemy Unknown: Shepard meets the Catalyst by Hoplite39 reviews
After defeating the alien leader in the temple ship, Xcom operative Colonel 'Spectre' Shepard meets a foe she had never met before called the Catalyst...Includes spoiler references for both ME3 and Xcom EU.
Crossover - X-Com & Mass Effect - Rated: T - English - Humor/Parody - Chapters: 1 - Words: 812 - Reviews: 5 - Favs: 2 - Published: 1/26/2013 - Shepard (F), Catalyst - Complete
Children of the Sky by Gibelyou reviews
When hostile aliens attack Earth, the Senshi must band together with the best our planet has to offer!
Crossover - Sailor Moon & X-Com - Rated: K - English - Sci-Fi/Adventure - Chapters: 2 - Words: 5,677 - Reviews: 9 - Favs: 12 - Follows: 20 - Updated: 12/20/2012 - Published: 4/29/2011
Earth 23 by 12951-V-Cydonian-Zoombian War
Crushed by the London Eye, Naomi wakes up surrounded by her sisters, only they're not her sisters. (This is a continuation of Future Fight after Naomi is crushed. Reviews Welcome.)
Crossover - X-Com & V, 2009 - Rated: K+ - English - Adventure/Sci-Fi - Chapters: 3 - Words: 2,469 - Published: 12/20/2012
The New One's Destiny (Going through revision) by SniperInTheHouse reviews
Sacrificing his life to save earth he is sent to a new universe. Full of Xenos hate boils in his blood. Will Merc continue his Xenophobic and rip the Normandy crew apart or become a savior to humanity. Discontinued due to a better story done so now theres finally a small group of cross overs with xcom
Crossover - X-Com & Mass Effect - Rated: T - English - Adventure/Mystery - Chapters: 8 - Words: 10,390 - Reviews: 14 - Favs: 9 - Follows: 13 - Updated: 12/10/2012 - Published: 11/7/2012 - Shepard (M)
XCOM: Viral Offense 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 nasty surprise. Rated for language and violence.
Crossover - X-Com & Prototype - Rated: T - English - Horror/Sci-Fi - Chapters: 6 - Words: 9,848 - Reviews: 58 - Favs: 139 - Follows: 183 - Updated: 11/25/2012 - Published: 10/24/2012 - Alex M./Zeus
Meteor Fall by 12951-V-Cydonian-Zoombian War
Amnesia, only 4 members of the team made it off of the Zoombian Ships, but even worse, only 3 made it to Earth. Causing Each other Grief as they go, can the four regroup or is all hope lost. Reviews Welcome. PS. Vs and X-com are in it later, please bear with it.
Crossover - X-Com & V, 2009 - Rated: K+ - English - Adventure/Sci-Fi - Chapters: 3 - Words: 1,744 - Updated: 9/18/2012 - Published: 9/8/2012
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