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Mass Effect: The New Journey » by Arashi the Solar Phoenix
During a Joint Deployment, the UNSC Infinity and Her Sangheili allies are suddenly thrown into a new Galaxy, and end up near Charon before the Systems Alliance discovers the Charon Relay. Alliances are forged and how will the galaxy react to an aggressive humanity that not only doesn't use Mass Effect technology, but will not let anyone stand in their way of expansion? AU PreME1Halo & Mass Effect, T, English, Sci-Fi & Adventure, chapters: 20, words: 190k+, favs: 2k+, follows: 3k+, updated: 6/11/2019 published: 1/26/2014
4k+ The Last Spartan » by DinoJake
An AU fic in which the Halo and ME universes share the same galaxy. After a well deserved rest in Cryo-Sleep, Master Chief finally awakens...to a whole new galaxy.Halo & Mass Effect, T, English, Sci-Fi & Adventure, chapters: 55, words: 489k+, favs: 4k+, follows: 4k+, updated: 12/31/2018 published: 5/2/2010, Master Chief/John-117
891Halo: the Art of War » by Havoc-legionnaire
AU. One small divergence, the smallest of errors, and the balance of fate tips. It is 2552. Reach is spared, for now. Operation Red Flag goes forth. The Covenant will learn that this war that they have started 27 years ago have only just begun.Halo, T, English, Sci-Fi & Adventure, chapters: 35, words: 181k+, favs: 1k+, follows: 1k+, updated: 2/27/2016 published: 10/2/2010, Master Chief/John-117, Prophet of Truth
978The Heavens Shall Tremble » by Full-Paragon
Sequel to And the Meek Shall Inherit the Galaxy. It's probably dead forever guys.Mass Effect, T, English, Sci-Fi & Horror, chapters: 23, words: 95k+, favs: 1k+, follows: 1k+, updated: 9/21/2015 published: 10/25/2013, Garrus V., Liara T'Soni, Tali'Zorah, Shepard
980 In Infinitum: First Contact » by Victor Weiss
In the year of 2581 the UNSC stumbles across a discovery hidden beneath their noses and now a new gateway to life outside of the Forerunner space is opened and with it comes all new challenges and rewards. Its time for First Contact. OC centric, some world building as needed and war. Lots and lots of war. Rated T for blood, language, violence and gore.Halo & Mass Effect, T, English, Sci-Fi & Suspense, chapters: 27, words: 149k+, favs: 1k+, follows: 1k+, updated: 1/23/2015 published: 9/19/2013
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The Life » by casquis
The Great War was a long one, millions made it, more didn't. Frank is an ODST, a human just like us, that has managed to survive the most grueling battles for years. With so much experience under his belt he has some amazing stories to tell. This are the life stories of an immature, not-all-in-there, and talented Marine just living, fighting, and being plain badass during the war.Halo, T, English, Sci-Fi & Adventure, chapters: 230, words: 1622k+, favs: 1k+, follows: 767, updated: 12/12/2014 published: 6/20/2011
777 A Change of Fate » by DX1998
While fleeing from the Ori after the death of their alllies, the Odyssey is near destruction. In a desperate bid for surviaval, a future version of Samantha Carter develops a plan to use the power of the Ori beam to save the ship. But it goes horribly wrong...now the cruiser is in a new reality, and a new war. Can they help their cousins in the UNSC? Or will the Covenant prevail?Stargate: SG-1 & Halo, T, English, Adventure, chapters: 29, words: 104k+, favs: 1k+, follows: 1k+, updated: 10/7/2014 published: 1/17/2013, S. Carter, Master Chief/John-117
358 Veteran Player, Different Game » by D4RKL0RDR3V4N
A new age has dawned. New alliances have formed. Old grudges have been forgotten. But darkness looms on the edges of dark space, and it has sworn none shall escape the coming fire... AU post-Halo 3, pre-Mass EffectHalo & Mass Effect, M, English, Sci-Fi & Adventure, chapters: 35, words: 56k+, favs: 390, follows: 468, updated: 7/28/2013 published: 5/31/2012, Fred-104, Admiral Hackett, J. Garson