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The Sword of the Geth by Doctor poo and the TURDIS reviews
Dying on Mantle's Approach, Cortana wakes up in an unfamiliar environment. In her drive to get home, she 'employs' the assistance of the local synthetics. She never wanted to be a galactic overlord. But a UNSC AI in an environment woefully unprepared for one of her caliber makes an easy one.
Crossover - Halo & Mass Effect - Rated: T - English - Sci-Fi/Humor - Chapters: 9 - Words: 35,279 - Reviews: 151 - Favs: 336 - Follows: 475 - Updated: 7h - Published: 11/23 - Cortana, Shepard
Midnight Falls by Ilveaztea2 reviews
Spartan B311 was fighting alongside B312, Noble Six, as they made their last stand on Reach. Then with no explanation, B311 wakes up in the ruins of what was once a city on earth and that the year is 2087 instead of the year 2552.
Crossover - Halo & Fallout - Rated: M - English - Sci-Fi - Chapters: 1 - Words: 2,267 - Reviews: 1 - Favs: 3 - Follows: 4 - Published: 9h - OC, Sole Survivor
Only in Death Does Duty End by Cypher1597 reviews
Spartans are instruments of war. They are molded, shaped, and bred to spill the blood of humanities countless enemies in the defense of mankind. They are not peacekeepers. They are not peacemakers. But duty alone will force a single Spartan to uphold a fragile peace or watch everything humanity could one day achieve burn. On the blood of their fathers and the blood of their sons.
Crossover - Halo & High School DxD/ハイスクールD×D - Rated: M - English - Supernatural/Suspense - Chapters: 1 - Words: 4,121 - Reviews: 8 - Favs: 39 - Follows: 47 - Published: 13h - OC
Freedoms Binds by kivey reviews
You want and wish. People always say watch what you wish for. Will this wish lead to ruin, or turn out to be what he always dreamed? Sometimes you don't make a wish, and yet an invisible seemingly heartfelt one exists. Is this really what you want? You might not have said it but are you ready to face it?
Crossover - Harry Potter & Halo - Rated: M - English - Chapters: 3 - Words: 4,313 - Reviews: 5 - Favs: 16 - Follows: 20 - Updated: 13h - Published: 9/5/2015
Halo: The War on Sera by SwedishEmperorThe1 reviews
After the final battle at the Ark, the Master Chief and his friends finds themselves on the obscure planet of Sera. There they've to team up with Sergeant Marcus Fenix and his Delta Squad to once again save humanity from enemies desiring its extermination, as well uncover hidden conspiracies that could determine the very fate of the universe.
Crossover - Halo & Gears of War - Rated: T - English - Sci-Fi/Adventure - Chapters: 5 - Words: 54,164 - Reviews: 61 - Favs: 140 - Follows: 159 - Updated: 14h - Published: 12/26/2015 - Master Chief/John-117, Marcus F.
Galactic Conflicts: Tales of First Contact by TheDoctor1998 reviews
Humanity and its allies have stood strong after the Great War with the Covenant. Follow the Systems Alliance as it goes through a first contact nearly as disastrous as the one that lead to the Great War.
Crossover - Halo & Mass Effect - Rated: M - English - Sci-Fi - Chapters: 6 - Words: 24,346 - Reviews: 92 - Favs: 217 - Follows: 316 - Updated: 18h - Published: 2/6
An Artificial Life by Grocamol reviews
What do you do when so much is thrown at you? What do you do when YOU wake up as an A.I.?
Crossover - Halo & Youjo Senki: Saga of Tanya the Evil - Rated: T - English - Chapters: 1 - Words: 2,051 - Reviews: 4 - Favs: 28 - Follows: 41 - Published: 19h - Cortana, SPARTAN-B312/Noble Six, Tanya
Project Atlas by Masso 2010 reviews
The Spartans are trained to be unthinking, unflinching and unmoving in the face of the impossible. Project Atlas is so much more, when humanity looks up into the sky they can see Hope, Justice, Reverence. When those that seek to hurt humanity look up into the sky, they see the warrior, the monster, the demon. To those who seek the destruction of humanity, he is the Cataclysm.
Crossover - Superman & Halo - Rated: M - English - Adventure/Sci-Fi - Chapters: 23 - Words: 168,959 - Reviews: 201 - Favs: 445 - Follows: 524 - Updated: 22h - Published: 4/17/2022 - Clark K./Kal-El/Superman, Master Chief/John-117
Only in Death Does Duty End - Repost by LaEmporoar reviews
Spartans are the protectors of humanity. Headhunters are the sword of humanity. Both are required to fight for their species unto their dying breath. However, when death finally comes is that duty maintained? Does it continue as long as the mind can remember it? Regardless of the answer, a Headhunter must find a way to continue his duties. Even if he is no longer human. - Repost
Crossover - Halo & High School DxD/ハイスクールD×D - Rated: M - English - Suspense - Chapters: 1 - Words: 117,894 - Reviews: 2 - Favs: 7 - Follows: 9 - Published: 12/2 - Complete
Semper Vigiles by Cypher1597 reviews
Headhunter. Spartan. Killer. Cyrus was many things, but killer is the most accurate term. Now he stands in a city full of killers all vying to be top dog. Let those fools climb over one another to reach the apex. It won't matter because soon it will all come crashing down. All of it, for we are but motes of dust and echoes. From dust we rise and to dust we go. Semper Vigiles.
Crossover - Halo & Cyberpunk 2077 - Rated: M - English - Adventure - Chapters: 9 - Words: 57,509 - Reviews: 125 - Favs: 403 - Follows: 462 - Updated: 12/2 - Published: 9/21
Harry Potter got trained by Driver1985 reviews
On the night Harry would have been dropped off by his Aunt, Dumbledore had someone else in mind. What if Harry was taken in by other strong people and they even decided to train him? Trained to be a Warrior by Wolves and the UNSC, he will change the world. OP, smart, trained Harry, small harem double cross with Witcher and Halo
Crossover - Harry Potter & Halo - Rated: M - English - Fantasy/Sci-Fi - Chapters: 87 - Words: 439,838 - Reviews: 365 - Favs: 770 - Follows: 901 - Updated: 12/2 - Published: 9/30/2021 - [Harry P., Hermione G., Daphne G.] Master Chief/John-117
story crossover ideas by modelbuilder1fan1
a listen of story ideas i had thought about
Crossover - Gundam Seed & Halo - Rated: T - English - Adventure/Suspense - Chapters: 1 - Words: 457 - Published: 12/2
The Iron Cross by Lighting wolf knight reviews
Scattered, in a world where their emperor never existed... The Ultramarines have but one purpose... Protect humanity and act among them. Rated T for violence, death, and profanity. Please ignore the latest review. I have blocked that user for insulting words and feelings i do not support.
Crossover - Warhammer & Halo - Rated: T - English - Adventure/Romance - Chapters: 39 - Words: 129,929 - Reviews: 82 - Favs: 176 - Follows: 218 - Updated: 12/2 - Published: 7/15 - Space Marines, OC, Arbiter, Linda-058
Noble Shinobi by LincyGirl reviews
Death comes to all of us, Noble Six knew of It, so when he died he accepted It and was ready to join his fellow spartans. He did not expect to wake up on world way more fucked up than his. (Classified M due to gore)
Crossover - Naruto & Halo - Rated: M - English - Sci-Fi/Adventure - Chapters: 1 - Words: 493 - Reviews: 2 - Favs: 4 - Follows: 6 - Updated: 12/2 - Published: 12/1 - SPARTAN-B312/Noble Six, Samuel-034, OC, Kakashi H.
No Gods, Nor Masters by Johnnieboy11 reviews
After the pyrrhic victory of the Human-Covenant War, the Covenant was split into many warring factions vying for the power of old. The UNSC was left, bloodied, but as the sole power in the Milky Way for now. After an incredible discovery within a set of Forerunner Ruins, an Exploration Fleet with Doctor Halsey at its head is sent out. What they find will change everything.
Crossover - Halo & Gate - Jietai Kare no Chi nite, Kaku Tatakeri - Rated: T - English - Adventure/Sci-Fi - Chapters: 37 - Words: 171,888 - Reviews: 736 - Favs: 1,161 - Follows: 1,424 - Updated: 12/2 - Published: 1/28/2022 - C. Halsey, OC, Itami, Tyuule
Many hands make light work by Polluxsashes reviews
A normal twenty-first century human mind stuck inside a Huragok, a Forerunner biobot, gets punted straight into the worst place anyone could ever be: Warhammer 40k. What is he to do but what he is made for? Beware all who call this horrid universe home, you will be 'halped'. First story on this site, updates every month. I have up to chapter 12 already written.
Crossover - Warhammer & Halo - Rated: M - English - Sci-Fi - Chapters: 13 - Words: 27,236 - Reviews: 122 - Favs: 405 - Follows: 556 - Updated: 12/1 - Published: 4/27
Mass Effect: Halo Codex Version by Vulture Electra reviews
What would happen if the universes of both Halo, Mass Effect, and Avatar(James Cameroon) were combine into one universe. What would happen had Halo Humanity had an earlier first contact rather than their first contact being with the Covenant. How would things played out, find out in this fanfic called Mass Effect: Halo.
Crossover - Halo & Mass Effect - Rated: M - English - Adventure/Sci-Fi - Chapters: 1 - Words: 1,200 - Reviews: 1 - Favs: 8 - Follows: 8 - Published: 12/1
Semper Vigiles Original Repost by LaEmporoar reviews
Headhunter, a program propagated by the Office of Naval Intelligence. After a final act of defiance against the Covenant, a Headhunter must find his place in a city ruled by corporate greed, bloodthirsty mercenaries, and roaming bands of vicious scavengers. It is the perfect hunting ground for one of ONI's most accomplished killers. Semper Vigiles - Always Vigilant. Repost
Crossover - Halo & Cyberpunk 2077 - Rated: M - English - Adventure - Chapters: 63 - Words: 422,943 - Reviews: 8 - Favs: 33 - Follows: 28 - Updated: 11/30 - Published: 11/29
Massive Reckoning: Interstellar Assualt by vmoneywashere reviews
In the 2700s, the Milky Way is flourishing. Access to Forerunner ruins has allowed the races of the galaxy to explore their home and new galaxies. Now, a new fleet, lead by an Ancient Punic Class Fleet Carrier, is moving to explore a new galaxy. Soon enough, the UNSC will find itself embroiled in a new Great War, with a few standing in the way of mass extinction. (slow updates)
Crossover - Halo & Mass Effect - Rated: K+ - English - Sci-Fi - Chapters: 2 - Words: 14,996 - Reviews: 22 - Favs: 122 - Follows: 181 - Updated: 11/30 - Published: 10/9 - P. Cole, OC, Admiral Hackett, Shepard
The Demon Of The Nine-Nine by SSJ Lone Wolf reviews
It had been ten years since Noble Six joined the NYPD, following the fall of Reach, quickly moving through the ranks and making detective, but when he is transferred to the 99th precinct he finds his life flipped upside down when he had to work alongside the eccentric squad of the Nine-Nine. If his own past doesn't drive him insane...they certainly will!
Crossover - Halo & Brooklyn Nine-Nine - Rated: M - English - Chapters: 21 - Words: 163,129 - Reviews: 676 - Favs: 916 - Follows: 1,019 - Updated: 11/30 - Published: 10/5/2021 - SPARTAN-B312/Noble Six, Jake P., Amy S, Rosa D.
ARES:The Gods of War by Johnnieboy11 reviews
Mankind's Greatest Hero has finished his mission once more. Saving Earth from the Didact and his weapon of mass-recruitment, the Composer, the Master Chief and his AI companion, Cortana, find themselves mysteriously transported to a strange variation of Earth, where machines rule the surface and mankind hides below. The SPARTAN and those that join will fight to Reclaim the world...
Crossover - Halo & Goddess of Victory: Nikke - Rated: T - English - Adventure/Sci-Fi - Chapters: 20 - Words: 72,885 - Reviews: 226 - Favs: 406 - Follows: 537 - Updated: 11/29 - Published: 11/29/2022 - Master Chief/John-117, Cortana, Commander, Rapi
Stargate Atlantis Fire Within by heavyneos reviews
Just as the Atlantis team think they have finally found a reprieve from the Wraith thanks to a fortuitous accident something hidden in deep space and from another world may bring more than one complication to the fight
Crossover - Halo & Stargate: Atlantis - Rated: T - English - Sci-Fi/Adventure - Chapters: 5 - Words: 20,668 - Reviews: 37 - Favs: 79 - Follows: 110 - Updated: 11/29 - Published: 9/8 - Rodney M., John S., OC
The Mantle of Remnant by KtyouVsWriting reviews
The Master Chief has saved Humanity at the cost of Cortana, one of his few remaining friends. More than he will admit, John relied on her, cared for her. To no longer have her means to lose another part of his humanity. Still the universe keeps going and once again, he is called to serve and protect Mankind. Now he has a choice: does he brave Remnant alone or does he embrace help?
Crossover - Halo & RWBY - Rated: M - English - Adventure/Friendship - Chapters: 29 - Words: 161,368 - Reviews: 819 - Favs: 1,579 - Follows: 2,023 - Updated: 11/28 - Published: 5/16/2019 - Master Chief/John-117
World Eater by ArmadaScream reviews
Remnant is a land full of dangers. Filled with dark creatures, heartless beasts and vicious evil. Yet even so the world keeps turning and its inhabitants live their day to day life. But now an extraterrestrial plague has found its way onto the planet Remnant, and the Flood is coming.
Crossover - Halo & RWBY - Rated: T - English - Suspense/Adventure - Chapters: 2 - Words: 11,263 - Reviews: 16 - Favs: 23 - Follows: 38 - Updated: 11/26 - Published: 11/19 - Team RWBY, Ozpin, Pyrrha N., Gravemind
Halo: RWBY Evolved by Danilyss reviews
After what was thought to be a simple mission, team RWBY wind up as stowaways aboard a phantom on the Seeker of Truth as it rendezvous with the Fleet of Particular Justice in order to await for the arrival of the Pillar of Autumn. Now caught in a war none of the girls would ever have imagined, they must fight alongside the Master Chief and the Marines against the Covenant.
Crossover - Halo & RWBY - Rated: T - English - Sci-Fi/Horror - Chapters: 4 - Words: 34,374 - Reviews: 36 - Favs: 90 - Follows: 136 - Updated: 11/26 - Published: 5/12 - Master Chief/John-117, A. J. Johnson, Cortana, Team RWBY
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