''[[http://www.fanfiction.net/s/8781720/1/The-Onyx-Stars The Onyx Stars]]'' (Website/SpaceBattlesDotCom [[http://forums.spacebattles.com/threads/the-onyx-stars-halo-mass-effect.243712/ discussion thread]], continued [[http://forums.spacebattles.com/threads/the-onyx-stars-the-second-thread.274313/ here]]) is a ''Franchise/{{Halo}}[=/=]Franchise/MassEffect'' crossover fanfic by Sith/The Hidden Sith.

'''Spoilers''' for ''VideoGame/{{Halo 4}}'' will ensue.

The UNSCS ''Infinity'' has successfully pursued and defeated the Ur-Didact [[AlternateUniverseFic before he could reach Earth]], but celebration is short-lived for a Slipspace accident on the home way shunts them into a strange new galaxy where there are marginally friendly aliens and the local human polity is not their own. As initial goodwill brought about by their assistance in fighting a common enemy fades into tension, however, shadowy powers disturbingly knowledgeable of the ''Halo''-group start making their moves.

!!This fanfic contains examples of:
* AIIsACrapshoot: Chapter 15 reveals that [[spoiler:Offensive Bias has become obsessed with recreating the Forerunners at any cost.]]
* AlternateUniverseFic: See above blurb? That's only the first and most obvious divergence from canon.
* AttackDrone: The UNSC employs these as part of the author's aim to defy the ModernStasis of canon.
* CallBack: The ''VideoGame/{{Halo 3 ODST}}'' group became SPARTAN-[=IVs=].
* CurbStompBattle: The snuffing-out of [[spoiler: Parangosky's conspiracy group. Serin Osman gets assassinated Zealot-style by Rtas 'Vadum, Naomi gets her neck snapped by Fredrick-104, and Admiral Harper downs the remainder of the Kilo-Five team with three perfect headshots.]] All in a matter of ''seconds''.
** The ''Infinity'' against just about everything. [[spoiler: The ''Normandy'' still got the kill-shot on Sovereign, though.]]
* DespairEventHorizon: In chapter 14 [[spoiler:after Lasky refuses to accept The Illusive Man/Michael Sullivan's offer of alliance, the latter stops trying to resist when the Bias tries taking over again.]]
* DidntSeeThatComing:
** The Illusive Man was expecting [[spoiler:Lasky to be slow and brutal about killing Batarians. He didn't expect Lasky to use only necessary force.]]
** He also didn't expect Lasky's enthusiasm about killing Brutes/Jiralhanae.
* FallenHero: Appears to be the case with the Illusive Man, who turns out to be [[spoiler:Michael Sullivan.]]
* FieldPromotion: Subverted. [[spoiler:John]] getting bumped up to Commander appears to be this at first, but turns out to be not on Lasky's authority but on the Joint Chiefs'.
* FixFic:
** [[spoiler:Cortana doesn't die.]]
** [[spoiler:Parangosky was executed for her crimes.]]
* HeKnowsTooMuch: In chapter 14 The Illusive Man executes Cerberus members who [[spoiler:know his real name.]]
* LegacyCharacter: In chapter 14 we learn that [[spoiler:there were Didacts before the [=IsoDidact=], and there will be one more Didact. All signs are currently pointing to John.]]
* MeaningfulName: "Project Tenzing" is about the [[spoiler:UNSCS ''Everest''.]][[note]][[http://en.wikipedia.org/wiki/Tenzing_Norgay Tenzing Norgay]] was the sherpa accompanying Sir Edmund Hillary to Everest.[[/note]]
* MythologyGag: Reapers being able to do StarKilling seems to be a reference to how ''Franchise/MassEffect2'' had an AbortedArc of a star dying prematurely, which was suggested to be due to artificial means out of reach to the Citadel races.
* NotSoStoic: John takes it badly when [[spoiler:Gray Team get {{Wetware Body}}ed and made to die ignobly.]]
* PragmaticAdaptation: The author deliberately made some changes to UNSC capabilities so they make more sense. Changed things include the excessively heavy MAC rounds and ModernStasis of the ground forces.
* ShoutOut:
** A subtle one in chapter 10, where John is overseeing the training of SPARTAN-IV teams [[Literature/ASongOfIceAndFire Iron and Throne.]]
** "117, if we all got what we wanted then I'd be [[Franchise/StarTrek an omnipotent being named after a letter of the alphabet and be trolling the very fabric of reality..."]]
* StarKilling: During the human-Covenant war, the UNSC tried this but could not get it to work (to their credit, the UNSC ''has'' managed to ignite gas supergiants into stars through copious nuking to trigger the fusion process, but then this is about destroying stars, not creating them). The Reapers, on the other hand, can.
* TakeThat:
** On [[spoiler:Parangosky's actions]]: "[[Creator/KarenTraviss What a travesty.]]"
** When Palmer says "We're giants" in chapter 4, Lasky shoots her a DeathGlare. Also counts as an InUniverse TakeThatUs.
* WhamEpisode:
** Chapter 14. [[spoiler:The Illusive Man is Michael Sullivan. The "Full Mother" the Geth worship is ''some'' form of Cortana. The Reapers have begun their attack on the new Reach.]]
** Chapter 15. [[spoiler:Arcturus Station has fallen. The new Reach has fallen. The Reapers, with Offensive Bias at their head, are attacking Earth.]]
* WhamLine: A rather low-key one in chapter 3 regarding [[spoiler:Sovereign]]:
--> "No sir, I am picking up [[spoiler:Forerunner alloys]] however on the largest vessel and zero organic life signs."
* WorfBarrage: In chapter 15, Infinity throws everything she has at [[spoiler:Offensive Bias' flagship]] and doesn't do anything more than dent the shields.