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RU-BY Chibi by Stark Savior-the mad engineer
Vahlen's gotten her hands on a machine that selectively alters reality to a relative normal. How bad is Bradford going to freak out, and how much havoc will XCOM's soldiers wreck on the Avenger?
Crossover - X-Com & RWBY - Rated: T - English - Humor/Parody - Chapters: 1 - Words: 1,134 - Follows: 2 - Published: 11/22/2019 - OC, Team RWBY, Team JNPR
X-COM Ad Infinitum by Xphonias reviews
X-Com, Mass Effect Crossover, Space Engineers elements. As Humanity pushes off the Ethereal threat a cycle continues, while a vast, unknown Galactic Civilization lives right upon its borders, bringing with it possible friends, or foes.
Crossover - X-Com & Mass Effect - Rated: T - English - Sci-Fi/Adventure - Chapters: 7 - Words: 6,725 - Reviews: 14 - Favs: 88 - Follows: 135 - Updated: 10/25/2019 - Published: 3/25/2018
Of Avatars and Harbingers by The Shadowscythe reviews
Humanity, a species that has been invaded twice by the Ethereals, their thrall species and occupied by the ADVENT coalition have finally left the Sol system and expanded into the stars. They knew the Ethereals feared something bigger & badder than themselves. They knew the Protheans has been wiped out by the same threat. The time of the cycle has arrived and extinction awaits all.
Crossover - X-Com & Mass Effect - Rated: M - English - Sci-Fi/Horror - Chapters: 17 - Words: 73,632 - Reviews: 37 - Favs: 145 - Follows: 204 - Updated: 10/16/2019 - Published: 11/18/2018 - OC, J. Garson, Shepard, OC
A New Unknown by Twisted Fate MK 2 reviews
On their way to Atlas, after a long day of fighting, the group begins to feel exhaustion take them. Setting down, they settle in for an evenings rest and a finished trip to Atlas the next day. But as they rest, an enemy unknown reaches to their world, in search of a 'new breed', and rips them from their home. Big thanks to Le Vampire for the beta! (Planning and Beta Hiatus)
Crossover - X-Com & RWBY - Rated: T - English - Adventure - Chapters: 3 - Words: 18,114 - Reviews: 16 - Favs: 36 - Follows: 53 - Updated: 10/16/2019 - Published: 9/12/2019 - Ruby R., Weiss S., Blake B., Yang X.L.
Our Last Hope by Johnnieboy11 reviews
The Human-Ethereal War, colloquially known as the Long War by those who were on the front lines, has ended with the death of the enemy's leaders aboard their own Temple Ship. For XCOM, a new mission comes:to find the lost Strike-1, their Elite Troops and return them home. For Strike-1, a new objective arises in the fields and cities of a new world, to win a new Long War.
Crossover - X-Com & RWBY - Rated: T - English - Romance/Sci-Fi - Chapters: 2 - Words: 4,890 - Reviews: 5 - Favs: 17 - Follows: 26 - Updated: 10/4/2019 - Published: 10/1/2019 - OC, Van Doorn, Team RWBY, Team JNPR
Inheritance by BrightestDarkness reviews
A century after the Ethereal War, Posthumanity stands scarred, hardened, and vigilant of what lies within hidden within great bleak of the interstellar. Now, Gifted with psionics and endowed with artifacts of technology beyond their collective maturity to wield, the Union faces the civilizations of the greater galaxy as it comes to decide who they wish to become.
Crossover - X-Com & Stellaris - Rated: T - English - Sci-Fi/Western - Chapters: 1 - Words: 4,555 - Reviews: 1 - Favs: 9 - Follows: 11 - Published: 9/2/2019
En otro mundo y con todas las habilidades de la fantasía ¿Ahora que? by BrickyLemming
Dios accidentalmente me mató y como compensación me envío a otro mundo, con una misión y con la posibilidad de aprender todas las habilidades de dan hacia de mi mundo y ahora ¿Que haré con mi nueva vida? La mayoría las ideas que se usarán en esta historia no son mías. Derechos reservados a sus respectivos creadores.
Crossover - X-Com & Re:Monster/リ・モンスター - Rated: M - Spanish - Sci-Fi - Chapters: 4 - Words: 5,239 - Favs: 5 - Follows: 6 - Updated: 7/18/2019 - Published: 3/31/2019
X-Ray Victor Charlie:The Chronicles of Strike-3 by Johnnieboy11 reviews
Her death at the hands of an Imperial Sniper during the battle of Marberry wasn't all it seemed... Isara Gunther, a member of Squad 7 and a Hero of Gallia now stands face to face with a war bigger than she could understand and few friends to turn to but the organization that now hosts her. And a Long War awaits our young hero-to-be.
Crossover - X-Com & Valkyria Chronicles - Rated: T - English - Romance/Sci-Fi - Chapters: 14 - Words: 45,623 - Reviews: 13 - Favs: 39 - Follows: 50 - Updated: 6/24/2019 - Published: 10/14/2018 - [OC, Isara G.] [Bradford, Dr. Vahlen]
The X-COM Files by Illuviar reviews
Conspiracies, Cults, strange events and attacks by impossible creatures and that is just the tip of the iceberg. Can a world plagued by so much strife and unusual activity prevail and get together to face that might be their greatest challenge yet or would the eventual arrival of the Ethereals be seen as a ray of hope for a civilization at the brink of collapse?
Crossover - X-Com & X-overs - Rated: M - English - Sci-Fi/Mystery - Chapters: 10 - Words: 39,001 - Reviews: 9 - Favs: 24 - Follows: 30 - Updated: 5/30/2019 - Published: 9/28/2018
Twenty Years Late by A Very Thirsty Megalomaniac reviews
It's hard for the Ethereals to invade when someone else got there first.
Crossover - X-Com & Half-Life - Rated: T - English - Sci-Fi/Adventure - Chapters: 18 - Words: 91,352 - Reviews: 38 - Favs: 84 - Follows: 83 - Updated: 5/20/2019 - Published: 5/14/2018 - Bradford, A. Shephard, Barney C., The Combine
The Long War to Freedom by kdports
As Earth capitulates to the Ethereals four elite soldiers are released into Eastern Estonia to create the foundations of a resistance movement against the aliens. Meanwhile, with the Galactic Senate afraid of war, Jedi Master Bo'Kanna sends a small espionage team to record evidence of Ethereal atrocities on Earth.
Crossover - Star Wars & X-Com - Rated: T - English - Sci-Fi - Chapters: 2 - Words: 1,716 - Favs: 4 - Follows: 2 - Published: 5/19/2019
Shattered Fate by Illuviar reviews
The year is 2175 and the galaxy is at peace. In the Terminus Systems, Battarian sponsored pirates gather, willing to test the resolve and capabilities of the System Alliance. At a X-COM facility, the last surviving soldier from the last war has been released from stasis, ready to be healed. Meanwhile the Ethereals plot in the shadows beyond the Relay Network and Nazara awakens...
Crossover - X-Com & Mass Effect - Rated: M - English - Sci-Fi/Adventure - Chapters: 26 - Words: 80,121 - Reviews: 86 - Favs: 297 - Follows: 388 - Updated: 4/19/2019 - Published: 2/3/2016
StarCraft II: Selfish Gene by edric2016underwood reviews
Jim thought it was over when Sarah Kerrigan killed by Emperor Mengsk's forces on Char. However, Sarah was brought back to life in secret by a mysterious snake lady called herself 'Dr. Vahlen' and a little girl looked like Sarah's younger self. (This StarCraft II AU happened after XCOM 2: War of the Chosen.)
Crossover - StarCraft & X-Com - Rated: T - English - Sci-Fi/Suspense - Chapters: 2 - Words: 8,441 - Reviews: 2 - Favs: 6 - Follows: 6 - Updated: 4/18/2019 - Published: 3/17/2019 - [Sarah K., James R.] Dr. Vahlen, OC
Tales from Within: expanded stories from RWBY Within by GryffenofSannGal reviews
Yet another expansion to the crossover series from DrAmish, RWBY Within. More or less, these are postings of logs and other materials from the REMCOM RPG site. With permission from the author himself, these logs range from semi-canon to canon. These stories may shed some insight of the vast, untapped universe of a world of an Enemy Unknown and the world of bloody evolution.
Crossover - X-Com & RWBY - Rated: M - English - Chapters: 16 - Words: 106,585 - Reviews: 2 - Favs: 17 - Follows: 20 - Updated: 4/16/2019 - Published: 6/24/2018
Zero Chance for Victory by AnonymousInsomnia reviews
Louise Vallière disappeared from Halkeginia on the day of the Springtime Familiar Summoning Ceremony, and landed in a strange world called "Earth." There, the chronically-exploding mage found herself caught in a titanic struggle between humanity's totalitarian overlords and a small but strong resistance group known only as the Extraterrestrial Combat Unit.
Crossover - X-Com & Familiar of Zero - Rated: T - English - Sci-Fi/Fantasy - Chapters: 2 - Words: 9,170 - Reviews: 16 - Favs: 70 - Follows: 103 - Updated: 3/4/2019 - Published: 7/29/2018 - Bradford, OC, Louise, Saito
Warframe: The Invisible War by gh0st3 reviews
It's been 10 years since Ballas took Lotus away from 005. She never stops her searching until she gave her idea to Ordis. From what she is expected to enter a new kind of war. She has many questions with her own mind. Will she play her part as a lone soldier or join with Xcom? Perhaps will she use her P.O.T.A.T.O. from Darvo's idea? *Spoilers from Second Dream and War Within*
Crossover - X-Com & Warframe - Rated: T - English - Sci-Fi/Adventure - Chapters: 4 - Words: 8,198 - Reviews: 9 - Favs: 15 - Follows: 25 - Updated: 2/3/2019 - Published: 5/24/2018
Unknown Contact by ecarden reviews
The obligatory Mass Effect-XCOM crossover, just set a little earlier than most. The Migrant Fleet is looking for new worlds, new tech, new allies. Humanity would very much like to not be exterminated by aliens from beyond the stars. SYNERGY!
Crossover - X-Com & Mass Effect - Rated: M - English - Adventure/Sci-Fi - Chapters: 17 - Words: 121,962 - Reviews: 126 - Favs: 329 - Follows: 477 - Updated: 1/9/2019 - Published: 6/15/2017 - U. Wrex, Tali'Zorah, Joker, Shepard
A Battle of Wills by insinr8 reviews
Following the destruction of the Temple Ship, humanity rises to become stronger than ever, and is determined that they will never again allow any enemy to repeat what the Ethereals did. In Vigilo Confido.
Crossover - X-Com & Mass Effect - Rated: M - English - Adventure/Sci-Fi - Chapters: 59 - Words: 262,053 - Reviews: 789 - Favs: 1,185 - Follows: 1,428 - Updated: 12/5/2018 - Published: 7/4/2015
X-COM: The third war by TehArbitur53 reviews
Three years after a second defeat by the hands of Advent, The XCOM project puts all its hopes into a strange artifact, that promises to bring them heroes. What they get instead are twelve Huntsmen and Huntresses, seven Simulation Troopers, four members of an MMO party, and a Supersoldier. (Contains XCOM, RWBY, RvB, Halo and KonoSuba) (Rated M for Language, violence and Gore.)
Crossover - X-Com & RWBY - Rated: M - English - Sci-Fi - Chapters: 12 - Words: 55,417 - Reviews: 44 - Favs: 69 - Follows: 66 - Updated: 12/1/2018 - Published: 7/17/2017 - Bradford, Team RWBY, Team JNPR, Team CFVY
Ascension of Earth's Guardians by Ciroth reviews
In the wake of the revelations of the Elders' Avatar project, XCOM did what they always do: Anything they had to. Covering events from XCOM2, TFTD, The Martian and Mass Effect, this is the first book in the Protectors series.
Crossover - X-Com & Mass Effect - Rated: M - English - Sci-Fi - Chapters: 8 - Words: 82,116 - Reviews: 20 - Favs: 144 - Follows: 216 - Updated: 10/13/2018 - Published: 8/3/2018
Alienation by a-mild-looking-sky reviews
CIA agent William Carter never bargained on combatting an alien invasion. He certainly never bargained on combatting two of them. [The Bureau: XCOM Declassified/Alien crossover]
Crossover - Aliens/Predator & X-Com - Rated: T - English - Sci-Fi/Horror - Chapters: 10 - Words: 37,994 - Reviews: 28 - Favs: 9 - Follows: 6 - Updated: 10/6/2018 - Published: 3/1/2018 - Alien/Xenomorph
Reign of terror by madmax2910 reviews
What would happen if regular military had stopped Reign with lethal force?
Crossover - Supergirl & X-Com - Rated: T - English - Sci-Fi/Suspense - Chapters: 9 - Words: 27,451 - Reviews: 12 - Favs: 16 - Follows: 21 - Updated: 9/30/2018 - Published: 7/11/2018 - Bradford, Van Doorn, Kara D./Supergirl, J'onn J./Martian Manhunter - Complete
GATE Thus XCOM Fought there by Cronus Prime reviews
After the Invasion of the Aliens in 2015, humanity proved it was a powerful force to be reckoned with. The Invaders were defeated and their technology was used to advance civilisation by several years. However, a mysterious GATE has appeared in Japan, and what had came through it has made a grave mistake...and Humanity doesn't take harm to it's people lightly. Viligo Confido!
Crossover - X-Com & Gate - Jietai Kare no Chi nite, Kaku Tatakeri - Rated: M - English - Sci-Fi/Fantasy - Chapters: 7 - Words: 36,863 - Reviews: 57 - Favs: 171 - Follows: 205 - Updated: 9/15/2018 - Published: 7/3/2018 - OC, Rory, Third Recon, Yao
War of Ages by Thunderbird013 reviews
It has been over a year since XCOM had finally defeated the alien menace. Now, when a new threat emerges, the secret organization will need to seek help from new allies, united across space and time. Undergoing re-write.
Crossover - X-Com & X-overs - Rated: T - English - Adventure/Sci-Fi - Chapters: 2 - Words: 19,313 - Reviews: 2 - Favs: 6 - Follows: 8 - Updated: 9/4/2018 - Published: 6/9/2015
The Battle of Yellowstone - A Story from The Human War by TonyJC reviews
The Battle of Yellowstone was the turning point in the Second Ethereal War, celebrated by humanity far and wide in their crusade against the Ethereal menace, but not everything the books about this bloody battle say are true... This story is a spin-off from the fanfic "The Human War", made by generatedname. This story has the author's permission and blessing to exist.
Crossover - X-Com & Mass Effect - Rated: M - English - Sci-Fi/Tragedy - Chapters: 3 - Words: 28,314 - Reviews: 2 - Favs: 14 - Follows: 18 - Updated: 8/22/2018 - Published: 5/24/2018
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