Halo (series)/WMG

Halo takes place in the same universe as Half Life
Well, think about it. The Covenant are the Combine, just with more alien, The Forerunners are probably Vortigaunt, Headcrabs are a simplified Flood, and the MJOLNIR Suits are Pimped-out HEV Suits. Hell, Buck even looks and sounds just like Barney Calhoun!!
 * More like a parallel universe or alternate reality. Why would the humans, Covenant, and Flood meet twice?

The Marathon Universe is the history of the first Human Empire.
We now know that humanity had an empire spanning the Orion Arm of the galaxy (working with the Prophets, ironically enough). We also know that there were other empires already in existence, like the Forerunners. Perhaps the Marathon universe is the history of this empire. A Forerunner, or perhaps Precursor or Jjaro device could cause most of human history to repeat itself to give us another chance. The Cyborg was hinted to be the reincarnation of every hero ever. Who's to say John-117, The Rookie, Noble Six and others aren't just new incarnations of him?

Buck was an Insurrectionist.
This is mainly based around his Expy status as an Expy of Mal. Now, while Buck is an expy of Mal, there's one major difference. While Mal was a Browncoat, fighting against the 'verse's government, Buck works for his. But who's to say this has always been the truth? Perhaps, before the Covenant arrived, he was an Innie. But, when they did arrive, he understood that the UNSC was the better of two evils and joined up. Now that the Human-Covenant War is over and humanity is literally down to a few hundred million and is ruled by the UNSC, I could imagine that he'll either return to his roots or do something similar to Mal, but with his squad. Either way, the UNSC better hope that he never discoveres what they did to create the Spartan-IIs or -IIIs, because as a Mal expy, he'll still have that Honor Before Reason Chronic Hero Syndrome that leads to him taking down your entire organization.
 * Well good luck to him on that. We know what a Spartan can do to ODST's...

Going with the Sliders version of alternate universes, the Necromorphs are an alternate version of Flood.
Sliders states that there is an alternate universe for everything. Dead Space is a universe where the Flood evolved differently and the Forerunners and Precursors never existed (or maybe they did), nor did any alien life seen in. The Flood and the Necromorphs have alot in common (I wouldn't be surprised if they had finished a marathon right before coming up with them). They both use biomass to create forms, they both also use this biomass to transform the walls of a place into a similar fleshy homes, they both are controlled by a tentacled hivemind also made out of biomass and they both have an affinity for turning body parts into weapons. Oh, and Blacklight might be another evolved differently version of them.

The Legendary Planet from the Halo 3 ending and the Halo 4 trailer is Reach
It would only make sense as in the opening and ending scenes of reach, an obviously crashed UNSC ship (presumably a frigate) lays behind Noble 6's helmet. And in the time period at the finish of Halo three, it would have been just after the planet had become cooled. The glyphs observed in the surface of the "Legendary Planet" are markings that the Covenant make on fallen human colonies after being glassed. One or more forerunner glyphs are etched into the surface with plasma, explaining the legendary endings markings. Soon after the glassing of the planet, it would have become alight, with unglassed surfaces continuing to burn, before years later turning to a more, Pre-War like state, explaining the crashed ship. Canon evidence from all Halo novels and games supports this theory.
 * Thing is, the LP seems to be tinted blue.
 * Joshed by Game Informer magazine. It's a Forerunner Sheildworld known as "Requiem".

Alternatively: The Legendary Planet is Onyx, and Halo 4 will feature Halsey and the other Spartans.
The Sentinels formed back into the planet's general superstructure after wiping out the human and Covenant forces outside. Kurt's nukes didn't actually destroy the entrance to the Dyson Sphere (remember how ineffective MAC rounds were against the Forerunner ship in 3?); they just closed it and it can now only be reopened from the inside. Along these lines, Halsey and the other Spartans have only just found the way to operate the gate as the Dawn arrives in-system (the interior of the sphere, being a pocket dimension, is massive), and they're now moving to respond to Cortana's beacon. Note that
 * Joshed by Halo: Glasslands.

The Forerunner are Vortigaunts from Half Life
Just a guess. And the Head Crabs are just a form of Flood. I just mostly want to see Chief and Freeman as Back-to-Back Badasses.
 * And the Legendary Ending planet is Xen.
 * Uh-oh... Halo 4 will be mostly jumping puzzles.

The Master Chief went insane at the end of Halo 2 after the earth was glassed by the Covenant.
After achieving victory in the space battle there would have been no reason to not glass the entire planet and dig up the forerunner technology with no resistance.
 * Except for the fact that glassing the planet might do a number on the very artifacts they're trying to find? They aren't indestructible.
 * And the VERY IDEA of turning weaponry against a Forerunner structure is considered blasphemy to them.

== The next game to feature John will have him fighting some new alien race while Cortana, whom we saw go Rampant at the end of Origins, goes  on him. == That is to say she tries to use him to become immortal and a god.

Firefly and Halo share a 'verse.
Now, at first this looks like an Epileptic Tree. However, bear with me. In some supplementary materials (on Halo..) it is said that humanity occasionally discovered planets with humans at different stages of development that they knew no ships had ever gone to. So, lets say a large group of ships leave Earth, some splitting off from the pack, taking those worlds. Most however, go to a single solar system, which becomes the one in Firefly. The Alliance fudges a few things, teaches lies, and everyone believes that the Earth was used up and they left. Firefly takes place in 2517, Pre-Human-Covenant War. Even if a Covenant ship showed up, it might get destroyed, and they would have no reason to attack human worlds yet. With there being Insurrectionists in the Halo 'verse, this would make perfect sense. The Pax may have even been made from a derelict Flood ship. It's not like the Alliance has any morals (come on, the Academy and Miranda prove that) and they lie to the people alot, so why not. Who knows, maybe the Chief and Cortana are about to land on a Core World. Oh, and we all know that if given the chance, Bungie would probably make this canon (There is a reason of the ODSTs voiced by Firefly cast members, and Buck is basically a copy of Mal (Besides for the Ink Suit Actor thing combined with the fact his actor is Nathan). They are self admitted Firefly fanboys (and girls).
 * Similar to how Sear from Gears of War could be in the same universe as well.

Connected (Last track on the Halo 2 Volume 1 Soundtrack) was actually written by Bungie.
First of all, it makes no sense when applied to the Halo universe. No 2 characters have that sort of relationship. Now, why would it be on the soundtrack? Well, most employees of Bungie are huge Firefly fanboys, and a Easter Egg/Tribute being put on a soundtrack would fit their style. If you haven't heard it, go look it up and then, if you know alot about Firefly you'll notice it fits if it were from the viewpoint of Simon to River. So, best Shout-Out/Easter Egg/Tribute ever?
 * I beg to differ. There are approximately 30 people in the Halo series with that sort of relationship - the SPARTAN-IIs. They see themselves as a family and trust eachother implicitly, and were often sent on dangerous missions where the only help would come from their fellow Spartans. That's how I've always interpreted the song.
 * The lyrics can also apply to the relationship between John and Cortana.
 * That's what I'm putting my money on. I mean, they are LITTERALLY connected; Cortana's using some of John's brain power to run.
 * Actually, I seem to recall on the Sumthing Music site (I got there from HBO-no, not the TV one) that it's supposed to describe the Halo gaming community. I'd point you to the reference if I could, but it's been so long since Halo 2 that I doubt that it would be still there. Perhaps the Internet Way Back machine could find it. Also, too lazy.

The Rookie is a clone of John.
Ok, first of all, in the Halo games, the MP maps/descriptions are canon. Second, one of the Halo 1 maps is described as a Spartan Clone Training Facility. Third, The Rookie never talks. Fourth, his initials are JD. John Doe, maybe? A clone of Spartan-117 used to actually get stuff done? Maybe...
 * The funny thing is that you're referring to the one map (Chiron TL-34) that might as well not be canon, hahaha. Bungie used to joke about bringing it back in later games just to piss people off, because everyone hated it so much (tiny rooms with teleporters linking them = everyone camps at a teleporter). I'm pretty sure it's gonna be the only map 343 Industries leaves out of the Updated Rerelease.
 * You sure the maps are canon? Because there aren't any green teleporters ever seen in either the books or the single player campaign.
 * Yes, the maps are canon. This has been said by Bungie and the [ HSB= ] (Halo Story Bible). Some maps are assumed to take place AFTER Halo 3 (Boarding Action and other teleporters and humans maps, for example). The Rookie was probably the first subject.
 * But S-117 speaks, albeit infrequently. The Rookie has to be a clone of someone quieter, probably Doomguy or Gordon Freeman.
 * No, as if he talked, questions would be asked, most of them being either "A clone?!" or "Doesn't he have a species to save, and why isn't he in his armor?"
 * If This is true, then The Rookie might be the original John-117 Clone that, for some reason didn't degenerate, or degenerate at lower rate, probably losing his voice in the process. This of course tell us that John-117 would kick ass even whit out the SPARTAN project.
 * Actually, it's only flash clones that degenerate. If he was a standard clone, then he'd be just fine. And the Rookie can talk; he does so, quite a bit, in the short story "Dirt".
 * No, as the ages aren't right (the Rookie and John). The Rookie is younger. But if the UNSC were to make a series of clones of him, set them up as ODS Ts or Marines or even S-IIIs they'd have a bunch of extra useful soldiers who can kick Covenant ass.

To add a more likely idea related to the below, The Flood are the original strain of the virus that became Redlight, and then Blacklight.
All there in the title.

Johnson is Alex Mercer.
At some point after Contact Harvest, Mercer adsorbed Johnson. This explains why he never dies from gunshots, and in Halo 3, gets back up from death very fast. Spark's lazer was just too powerful, though. Even though the real Johnson was a Spartan-I, Mercer wouldn't be able to become a member of the Flood because, well, there's no way to take over his nervous system, as he has none.

In Halo Wars,
.
 * See also this forum post.
 * Alternatively, Regret may simply be an idiot. His statements regarding the Covenant's war capacity could be due to a poor grasp of strategy and tactics. Certainly, he comes across quite poorly in Halo 2.
 * Just because the humans are at war with the Covenant doesn't mean that they are the only ones the Covenant may be fighting or defending against. Maintaining a solid defense force at home not only keeps you safe from potential enemies, but also allows you to supress rebellion - a significant concern for the Covenant.

Player 2 is Linda
Linda-058 was the last Spartan to accompany Master Chief during the battle of Reach, until she was presumably killed towards the end of the mission. Her body was placed in stasis onboard the Pillar of Autumn, and was ejected when the ship crashed onto Halo. . The two-player co-op game in Halo: Combat Evolved and Halo 2 is actually an alternate universe where she avoided getting shot.
 * Hasn't this been all but confirmed by the expanded universe? It says that Linda in fact survived the events of Reach and was put into cryogenic storage until she could be resuscitated. If we accept that a slight AU effect occurred and she was revived for the events of Halo, this makes a disturbing amount of sense.
 * This raises the question of what happened with her during the timeframe of Halo 3, since the Arbiter takes up the role of Player 2 there.
 * I'm sure they'll show up later in some crazy tactical shooter after Reach. Perhaps the first game 343 Industries makes? Perhaps some sort of Halo: Ghost Recon? Disclaimer: Never played Ghost Recon before.
 * Alternatively, Player 2 is an alternate version of
 * I'm sure they'll show up later in some crazy tactical shooter after Reach. Perhaps the first game 343 Industries makes? Perhaps some sort of Halo: Ghost Recon? Disclaimer: Never played Ghost Recon before.
 * Alternatively, Player 2 is an alternate version of

Master Chief is really...

 * An alternate universe version of Cloud Strife. Both are super-soldiers quite fond of using weapons way too big for them. Both have mysterious pasts. Judging from his stoicism and the fact we never see his face, we can deduce in a fanwanky manner that Master Chief has issues with self-identity, just like a certain blonde bishie we know! Not to mention, Master Chief's pretty handy with that energy sword... Don't be distracted by MC supposedly being ghostly pale and vaguely melancholy-looking underneath his armor and brunet. They have no proof.
 * A thawed out, mellowed out, older but still ass-kicking Duke Nukem. At the end of Duke Nukem Forever, DK will be placed into stasis to be thawed out when humanity needs him most again. Alternate theory: by the time Duke Nukem Forever is released, the actual real-life date will very nearly sync up with that of the Halo games.
 * Or....
 * Gordon Freeman, contracted by the G-Man to the UNSC. MJOLNIR Armor is derived from HEV Suit technology.
 * Of some relation to Samus Aran.
 * The Pyro.
 * A woman. Sure, we hear an obviously male voice when "he" speaks, but it wouldn't be terribly difficult to get some kind of device that changes how people perceive "his" voice. That's probably how Samus originally passed herself off as male.
 * Jossed by the first game. Which killed this WMG in the womb. Thus making the first game some sort of an "abortion" Jossing to the theory.
 * Hmm....
 * I don't know about you, but I haven't met that many women named John.
 * Could be a Shout-Out to Jeanne d'Arc?
 * No. He's explicitly male. People refer to him as 'he', and the books describe him pre-getting MJOLNIR'd up.
 * These so-called “books” are UNSC propaganda veiling Master Chief’s true gender.
 * A Special Circumstances agent. C'mon: he's never seen, fights to protect a race against a genocidal religious civilization, and is also fighting a great threat to life in the universe. The Culture would be all over this. Probably the Flood are (slightly) overexaggerated to get the humans to fight them more willingly (and are in fact just something the Culture thought might wipe out humanity so needed to be dealt with) and the Halos are just unneeded Orbitals being used as props to stage the whole 'meet the Flood' event (to convince the humans it was their responsibility. Who's to say the Culture couldn't have messed around with the Spartan development records and slipped the Chief in - c'mon, he's the only one that survived, so no-one could doubt any extra Culture developments he might accidentally let slip.
 * The Space Marine from Marathon. But that's not all, HE is in turnâ€¦ The special forces soldier from PiD!
 * This is actually the most likely. Bungie has stated that Halo was the spiritual successor to Marathon, and there's canon evidence to suggest that Pathways into Darkness and Marathon take place in the same universe.
 * Farther evidence supports this in the Legendary Easter Egg for Halo 3.
 * The forerunner of the Space Marines from Warhammer 40000. It's stated that the Primarchs and the 20 legions were created by now-lost genetic manipulation techniques by the Emperor personally. Obviously Master Chief is an early experiment by the Emperor to create a super-soldier, with great results.
 * An unidentified number of different people wearing the same armor. They all use loads of steroids and ecstasy and switch out with the next in line shortly before dying.
 * Haruhi Suzumiya.
 * Black. Just an idea I had, nothing really to back it up. And I haven't read any of the supplementary material to see if their is anything to contradict it, though I have heard his skin described as "pale".
 * Jossed. The novel The Flood describes Master Chief with his helmet off: he is pale and has greying red hair.
 * The UNSC dossier The Flood is a carefully crafted UNSC counter-intelligence document intentionally disguising Master Chief’s true identity. Master Chief is obviously black, and any data being used in having this truth Jossed is merely flimsy UNSC misinformation.
 * John Spartan. His name isn't just a Shout-Out.
 * Captain America (comics) using one of Tony Stark's sets of power armor.
 * The God Emperor of Mankind, directly defending humanity.
 * LEEEEROYYYYY JENKINS!
 * Commander Shepard. There's a reason he reacts with almost no shock upon discovering the Flood -- he's already fought them.
 * As none of the above are necessarily mutually contradictory, all of the above.
 * Are you implying that Duke Nukem, Samus Aran, and Cloud Strife are all the same person? Makes sense.
 * Ender Wiggin. He has an AI that can communicate to him though his helmet and is an AI (jane). He is a super soldier and Wiggin was a tactical genius on EVERY level. This only works if he is a mirror universe Ender that discovered quickly another alien threat that might have allied to the Buggers and could not wander through the universe searching for a new home for the Hive Queen.
 * A drunk violent man with Pyscological problems who the ONI Picked off the strret to replace the orginal who got tired of this crap and ran away

Sergeant Johnson can fly
Bear with me. This one requires a bit of an explanation. My friend and I were playing through the last level of Halo 3 and had reached the point where Johnson arrives to help. Since Johnson arrives on the opposite side of a cliff and my friend didn't see him cross the ledge before showing up in front of him, it was logically concluded that Johnson can fly.
 * Further evidence can be found in the driving section of the same level. Think of all those convenient one way jumps, particularly . How could he have possibly made those jumps coming in the opposite direction? Easily, of course, because Sergeant Johnson can fly.
 * ... a Pelican, which could easily have carried him and his Warthog to where he could drive to the ledge. As to why you don't find his Pelican? Because most of the ring's superstructure has collapsed by the time you drive there, and it fell.
 * A Pelican? An unlikely story from an ONI operative trying to conceal Sergeant Johnson's mastery of flight.

Sergeant Johnson is Batman...
...and can breathe in space. This is how he survived the explosion in the first Halo. Also, by extension, he also has access to a multitude of awesome gadgets and toys. Hence his seeming ability to fly in Halo 3.
 * Maybe you should read First Strike. Canonically, Sergeant Johnson The Legendary secret ending to the first game has been confirmed to be non-canon.
 * UNSC propaganda to cover up the fact that Sergeant Johnson is Batman.
 * I think you need to re-read "First Strike". As I recall, Johnson was picked up along with a Pelican and a few spare soldiers. They had crazy hijinks that involved the destruction of a Covenant fleet.
 * Rereading "First strike" would accomplish nothing because the alleged novel is still UNSC propaganda to cover up the fact that Sergeant Johnson is Batman.

Sergeant Johnson is Commissar Yarrick and Sgt. Reznov
Being extremely Badass, Yarrick, while at the head of the Black Templars Crusade devoted to chasing Warboss Thraka, chased Thraka close to the Eye of Terror. A warp storm hit, and Yarrick's ship was transported to Terra circa 1940s. After fighting on the Russian side under the name Sgt. Reznov, Yarrick encountered the Emperor sixty years later, and in between commanding one Army Ranger to do everything, the Emperor gives Yarrick immortality. Yarrick lives until the mid 2500s, fighting alongside the first Space Marine, where he is nearly killed during the operations on the Ark, but lives on to enlist in the Ultramarines 38,000 years later, and working as a Scout Sergeant with an excellent mustache.

Sergeant Johnson really died in HALO
The Sergeant Johnson in HALO 2 and HALO 3 wasn't really Johnson. The REAL Johnson was at ground zero when HALO exploded, No One Could Survive That.
 * Again, the Legendary secret ending to the first game has been confirmed to be non-canon.
 * Again UNSC propaganda, this time to cover up the death and replacement of a beloved hero.
 * PLEASE. This is SERGEANT JOHNSON we're talking about here. A 100 million degree thermonuclear explosion wouldn't even slow him down. See below.

Sergeant Johnson is Immortal
Johnson was at ground zero when HALO exploded, No One Could Survive That... Unless Johnson could not die.
 * Sergeant Johnson is one of the immortals from Highlander.
 * Or the Emperor of Mankind, which dovetails into the Master Chief is a proto-Space Marine theory quite nicely: the Emperor was keeping a close eye on his experiment.
 * Sergeant Johnson is a Time Lord. Johnson doesn't fly, but uses his TARDIS to teleport to seemingly unreachable areas. This also explains Sergeant Johnson's "immortality." Johnson's interest in music and culture centuries past comes from places he's been.  Amongst Time Lords, he is known as The Sergeant, Master Chief and Cortana are his companions, and the his ever present cigar is his TARDIS.
 * And he kills Dalek's with a Spartan Laser. Makes sense to me.
 * Seargent Johnson drank the Hourai Elixir. The Lunarians gave it to him as a test, as described in the official Touhou story Cage in Lunatic Runagate. Now he will live forever in eternal torment, unable to die or achieve enlightenment; obviously, he hasn't lived long enough for this aspect to manifest yet.
 * Wouldn't Johnson being immortal cause "and I must scream" at the end of Halo 3? Wasn't Instalation 00 specifically stated to be OUTSIDE the universe? If he was the only thing that survived then he would be trapped in a void filled with debris... or worse, more A.I.s, right?

Cortana is behind it all.
Think about it, Cortana took the Pillar of Autumn to Installation 04, She happily jumped into the Halo's network, she decided to blow up Installation 04 off her own back, while humans were still on the ring. She lied to Foehammer (at that point, only Cortana and the Chief knew that they were going to blow up Halo, surely informing their pick-up would be a sensible idea, instead she waits till the last moment, and tells her that the reactors are suffering a wildcat meltdown, omitting the fact that her and the Chief are responsible).

In the second game, she deliberately leaves herself inside High Charity's systems, knowing that the city is being overwhelmed by the Flood, and she fails to destroy High Charity, and appears to be co-operating with the Flood in the ending.

In the third game, her relationship with the Gravemind has obviously turned sour, but perhaps not until she got what she wanted from it. The Flood have a history of working with renegade AIs, as the Terminals show, and she doesn't seem too bothered when she and MC are stuck in the ship at the end, though logically, her limited 7 year lifespan could run out before they're picked up.

My theory is that Cortana has been using the Chief to get what she wants, an extended lifespan. Perhaps she discovered in Halo's systems a way to extend her lifespan, the AI 'imprinting' tech coming originally from the Forerunners. Maybe the human version is imperfect, or the human scientists deliberately limited the AIs' lifespan, fearing that the AIs would turn against them. Anyway, she finds out that this method exists, but not the details, so, in Halo 2, she deliberately stays behind, to get the knowledge from the Gravemind. All through the games, she's been acting in her own interests, not really caring about any other human except the Chief, as the first game's examples show, she is quite willing to sacrifice her own allies, and seems to want to cover up her and MC's actions on 04, perhaps to deflect suspicion of her motives.
 * This actually fits amazingly well with how the AIs' in Marathon acted. Durandal's ultimate ambition was essentially to become immortal, including a plan to escape the eventual closure of the universe and become god of the new universe that replaced it. Since Cortana is implied to be rampant herself, she might be doing the same thing.
 * And the one meatpuppet Durandal cares about is a cyborg supersoldier. Would be in keeping with tradition to adjust the plan a tad to ensure the one person liked survives.
 * The 7 year lifespan for smart AI's is no longer canon, the limitation only applies to dumb AI's.
 * You have it backwards. Smart AI's (based off of a human's mind) have a 7 year lifespan before they fall into rampancy. Dumb AI's don't tend to fall into rampancy.
 * Not anymore. It's been stricken out of canon. Smart A Is can survive for varying amounts of time now. Some don't go insane at all.
 * 7 years was never when the AI's go rampant. That's just the amount of time the UNSC lets them live for before deactivating them to prevent them from going rampant, probably found through some mathematical probability simulation.
 * Nothing has ever been stricken from canon, only the UNSC disinformation leading you to believe in retroactive continuity.
 * Actually, Foe Hammer and what was left of the Autumn's crew knew exactly what the Master Chief was going to do. In fact they captured the Truth and Reconciliation in order to escape the ring; Cortana and the Chief would rendezvous with them later. Unfortunately they never bothered to clear out all the Flood, and Lt. Melissa McKay knew what had to be done.
 * It's funny how close this theory is to what the Data Pads in Reach imply about A Is running the universe...

Alternately, Cortana is behind the entire plot of 'Halo 3'.
For this WMG, we presume that Cortana's still loyal to the UNSC and operating without agenda. She tried to destroy the In Amber Clad, but failed. This is entirely plausible, given the intelligence of Gravemind and his own hacking abilities. (Gravemind, it must be remembered, is no stranger to cybercombat with Forerunner AIs). So Cortana finds herself trapped, unable to override Gravemind's control of High Charity and In Amber Clad. What's she going to do?

Be very, very clever, that's what.

Gravemind is, obviously, interrogating Cortana for information. Also obviously, he's unable to simply strip her AI core open by brute force. Perhaps he lacks the ability to, perhaps Cortana would be able to wipe the data Gravemind is after in the process of dying. So Gravemind has to do a slow corruption strategy, ramping up the pressure gradually and stripping away her defenses and will bit by bit. This allows Cortana time to pretend to give in to pressure, to selectively leak data... to manipulate Gravemind's actions.

First, she informs Gravemind of what she knows of the Ark on Earth, ensuring that he will send a Flood-controlled cruiser to scout things out. Then she 'sneaks' a message onto that cruiser, telling the UNSC that a 'way to stop the Flood' exists on the Ark, on the other side of the portal. But there is no Flood cure on the Ark, of course. This we know. So why did Cortana lie to us and tell us there was?

To get Gravemind to believe it. Gravemind will overhear this message... its being carried on a ship he controls, for goodness' sake! But Cortana's pretending like she believes he hasn't.

And Gravemind hearing this about a 'solution for the Flood' guarantees that High Charity itself, with Gravemind on board, will go to the Ark. Gravemind's survival demands it. If any place in the universe could plausibly hold a cure for the Flood, its the Forerunner's last survival bastion, the Ark. Gravemind has to check this out. In addition, the remote control for the Halo detonation sequence is there, and its (as far as Gravemind knows) safely beyond range of the Halo rings.

So Gravemind is decoyed into going to the Ark. To the one place in the known universe that a Halo ring can be fired without destroying life in the galaxy, an artifical world "two the eighteenth light years from galactic center". And Gravemind is decoyed into going there, think it will be safe from Halo ring detonation, just as a replacement Halo is being built there. A Halo for which Cortana has a copy of its Activation Index.

Anybody think this is all a coincidence? Nope. Its a carefully-laid plan to lure Gravemind, and all the surviving Flood from the Delta Halo infestation(* ), out to where they can be safely exterminated without the pulse from a Halo ring actually hurting anyone in the galaxy. All of this improvised desperately by an AI finding herself imprisoned by the oldest and most horrifying entity in the history of sentient life in that universe, between the end of Halo 2 and the start of Halo 3. Way to go, Cortana.

(* ) Which is quite likely all the Flood left in the galaxy -- the Covenant Quarantine Fleet is sterilizing every ship from the High Charity outbreak, and every world that they touched, as they pursue High Charity to Earth. So the end of Halo 3 may very well have seen the final destruction of the Flood.


 * Just to nitpick here, but... Then she 'sneaks' a message onto that cruiser, telling the UNSC that a 'way to stop the Flood' exists on the Ark, on the other side of the portal. But there is no Flood cure on the Ark, of course. This we know. So why did Cortana lie to us and tell us there was? Cortana never said there was a "cure" for the Flood on the Ark. She said there was a way to destroy the Flood on the Ark.
 * Semantics. Destroying the Flood cures the galaxy if the infestation. The Flood can be viewed as a disease upon the galaxy. What's a cure if not eradicating the disease?

Awesome.
 * Due to the awesomeness of Cortana in the preceeding idea (not to mention the awesomeness of the troper who thought it up), we must conclude that Cortana is Batman! Well, actually, not quite. More like Cortana's AI is based on some descendant of Batman or one of Batman's proteges!
 * My theory is that the events of Halo 2 and 3 are a result of a Xanatos Gambit by the Forerunners to finally destroy the Flood. The information on executing the plan was hidden in the genetic memory of the Forerunners descendents, the humans. When Cortana interfaces with Forerunner tech in Halo she merely activates a part of her digital brain thats dormant in humans, allowing her to plot a course to destroy the flood without resorting to the great journey (ie kidnapping enough of every sentient species so that they survive, bringing them to the arc and then firing the rings to wipe out the flood). The Covenent's need for the great journey was the contigency plan, also put there by the Forerunners.
 * Pretty much confirmed by Karen Traviss's short story "Human Weakness".

Cortana went Rampant shortly after Chief put her into Halo's systems, and her rampancy changed her mission from protect humanity to protect Master Chief
Think about it, since Smart AI's apparently "think" themselves to death after rampancy, wouldn't something as advanced as Halo be a huge amount of information? Put yourself in Cortana's position. You would want every single piece of data from that place and integrate it into yourself for later use, which she DID with the index. The overload of data however messed with her, and she almost immediately went rampant. She managed to hold herself together though, and found out her commanding officer was walking into a trap and ordered Chief to go and save them. She watches Chief's entire battle to get out once he gets there. She loses track of him when Guilty Spark takes him, but she assumes that Chief has been killed and falls past her Despair Event Horizon. She thinks she's not only failed Chief and those who were on the Pillar of Autumn, but humanity as a whole, and fails her primary mission. However, when Chief is suddenly brought back to her in the control room, she has fallen so far that when she sees Chief, she is overcome with joy and anger at the same time, seeing a human alive and fairly well, yet angry because some other AI (Guilty Spark) is watching over him. She feels that Guilty Spark took Chief from her, so she takes the index from him as a sort of revenge. She had found out what Halo does, and was going to let it happen, until she saw Chief. At this point she has the overwhelming desire to keep Chief alive. Afterwards everything she does is to keep Chief alive. Blowing up the Pillar of Autumn was actually a way to get Chief onto the Longsword and off of Halo and the Flood. The Echo 419 pickup was when she realized that there might be a better way to keep him safe, but failed and fell back to her original plan. Cortana didn't care about Echo 419 in reality, but acted like she did so Chief wouldn't be nervous toting her around with him. When they got back to Earth, Chief was safe and Cortana felt she possibly didn't need to be with him every waking moment. However, once the Covenant attacked, she took the first chance she could to get back into his head, and "protect" him. When Cortana tells Chief to leave her behind on High Charity, it was so that she would in her mind commit a noble sacrifice and once again protect Chief. Then we reach the Cortana moments that were abundant in Halo 3. Cortana left her main self on High Charity, but not before leaving a fragment of herself still in Chief. As mentioned in Dr. Halsey's journal, AI's can fragment themselves and leave parts behind to work on something if the main "body" is needed somewhere else. However these fragments are unable to sustain themselves for extended periods of time without rejoining with the main AI. The part she leaves behind starts to speak to Chief throughout the game. Trying it's best to guide him with it's limited ability. This piece stays with Chief throughout the game until he finds the real Cortana back on High Charity. The Cortana moments previously in that level show Cortana growing more and more unstable, eventually giving into the gravemind. This is actually just the fragment losing it's ability to maintain itself, and it "dies" just before Chief reaches the main Cortana. This Cortana was no longer as far rampant as the previous one, as that fragment held quite a bit of data, so Cortana had less data to think herself to death with. This one was able to snap out of the funk she was in previously and regains her previous mission, to protect humanity as a whole, and guide Chief through the rest of the game. The irony comes at the end of the game. Chief is literally all that Cortana has left. Her mission has been renewed as protect humanity, but all she has to protect is this one human in front of her. While she does it because he is her friend, she is essentially doomed to die alone.

The Covenant were destroying Humanity to save it from the Flood getting their tentacles on us.
As the Good Book Says..., Genesis 9:11: "I establish my covenant with you: Never again will all life be cut off by the waters of a flood; never again will there be a flood to destroy the earth." What if that means that the Covenant were created as part of some convoluted plan - That the Flood would never get to destroy the Earth because the Covenant had "saved" us from enslavement by destroying us first?
 * Jossed in Contact Harvest, which establishes Truth is trying to exterminate humanity because he believes we're the Forerunners' descendants, and knowledge of that would potentially break the Covenant.
 * Not to mention the Covenant didn't even know the Flood EXISTED until 2530; FIVE YEARS AFTER THE WAR STARTED.
 * Contact Harvest is UNSC propaganda obfuscating the Covenant's true purpose.
 * You, sir, are UNSC propaganda attempting to discredit legitimate historical records by calling them UNSC propaganda.
 * YOUR MOTHER WAS UNSC PROPAGANDA!
 * Technically, fighting the Covenant did prepare the player and the rest of humanity for fighting the Flood. by developing and practicing space combat tactics and skills against the Covenant, Humanity (plus the player) were effectively toughened up and their chances of survival against the Flood were greatly increased, so this WMG does make sense.
 * Or someone spent way to much time trying to draw conclusions between the Bible and Halo...

The humans are the descendants of the Forerunners.
The Monitors recognize Master Chief and other humans as Reclaimers. And Earth has such significance to the Covenant that they send the Prophet of Regret there personally, not realizing that it's the human homeworld. The Forerunners seeded Earth with their genes, granting the primitive hominids their deadly intelligence. They also ensured that none of their technology would be easily found, so that humans would develop their own technology, have no reverence for the Halos, and be willing to destroy them if necessary.
 * The basic theory is all but painted in front of you with neon letters in the games and books-Forerunner technology reacts strangely to humans, humans can instinctively operate Forerunner equipment, the Convenant attacked humanity because of it, and Guilty Spark and the other Forerunner AI's confirm it.
 * I am trying to find some way to connect the Forerunners/Humans to the Ancients/Tau'ri (Humans) of Stargate. Anyone?
 * Think ATA gene. We're not evolutionary descendants, but Forerunner-created GMO monkeys.
 * And it's pretty much confirmed by the Forerunner Trilogy that the Forerunner's mucked about with human genetics.
 * The irony is that, in the Halo 3 ARG, it's actually made clear that the Forerunner found the Humans in the early stages of evolution. When you think about it,  At least that's my view of things.
 * This is now mildly supported by Halo: Reach.
 * Also the only known portal that leads to the Ark is located near the actually existing town Voi, which is located mere 1000 km away from the currently assumed region of Ethiopia, were modern humans evolved from more primitive ancestors.
 * I think you need to go read the Terminals in Halo 3. It's pretty clearly spelled out that the Forerunners and humans are two distinct species. And the idea of "inbreeding" is ridiculous; not only are we an alien race, but there is evidence of homo sapiens existing up to 250,000 - 140,000 years ago. The Forerunner were last on Earth around 100,000 years ago. What IS clear is that the Forerunners intended humanity to be their successor, explaining why only humans can activate the Halo Array.
 * Cryptum explicitly Josses this. Right from the start it outright says that humans and Forerunner are different species. And, for that matter, the Forerunners

The Forerunners where the Toclafane from Doctor Who.
They were floating spheres that spoke like creepy children and. Maybe Guilty Spark wasn't as artificial as he first seemed.
 * Jossed by SO MUCH STUFF. Not the least of all the Forerunner Trilogy by Greg Bear and the Halo Legends anime "Origins".

Master Chief managed to continue being a Space Marine, even after the events of Halo 3 where he is separated from humanity, and there supposedly is nothing left to kill.
You know how the Master Chief and Cortana are stuck drifting in half a frigate at the end of Halo 3, and how Master Chief went into cryogenic suspension? By this time, there is nothing left to kill, at least not readily available, and the Flood were discouraged from fighting him because he kept killing them, finishing with a massive explosion at the end of Halo 3 that killed the Ark. Now that the Covenant were friends, and the Flood refused to fight him anymore, what could he possibly kill? Simple. When you finish the game on Legendary, you see how the half-frigate is drifting near a planet or something. This is one of Earth's colonies, from the Dead Space universe. Master Chief gets out of cryosuspension, and lands on the planet, picking the random name Isaac Clarke. He looks at joining the legion of Space Marines, but decides that they are all Red Shirts, and doesn't want to save their asses in the event anything bad happens. So he takes the job of an engineer, with Cortana hiding in his suit and being the one who keeps warning him about vacuum and zero-gravity environments. He manages to get stationed on the USG Kellion, and they get called when the Ishimura sends its distress signal. When they crashed onto the Ishimura, it isn't long before Master Chief discovers a new enemy to kill: the Necromorphs. With glee, he picks up a Plasma Cutter and starts cutting them up.

Short version: Isaac Clarke is really the Master Chief.


 * Dude, the Necromorphs are totally a different species of Flood.
 * Okay. But is Clarke seven-feet tall?
 * He does slouch a bit. Bad post-cryo posture?
 * Impossible. You CAN'T have bad posture in cryo-sleep.
 * Also; if Issac Clark was the Master Chief, why wouldn't a single punch from him decapitate a Necromorph? And don't say it's his armor. The Chief killed three ODST's at AGE 14.

SGT. Johnson has laser eyes.
Church's cousin's neighbor said he does. I see no reason to doubt.
 * That explains why his Spartan Laser was fully charge

Halo and Metroid are in the same universe.

 * You may think that Metroid would come after, having much more advanced technology. You would be wrong. Halo comes after Metroid. The "humans" in the Metroid series are actually the forerunners. When they learned of the Chozo and their creation of the Metroids to stop the X parasite, they ignored the obvious difficulties and attempted to create their own super-species in order to stop some stronger villain later on in the series. The super-species, of course, went rogue, becoming the flood. So the forerunners began construction of the Halo rings in order to contain, or if absolutely needed, destroy the flood, leading to the extinction of the forerunners. Fortunately, they were prepared for this, and humanity was restarted on earth. Hey presto history leading up to the Halo series. Of course the forerunner architecture is different from the architecture in Metroid, leading me to believe that the flood are in the far future of Metroid, which would explain why they needed the flood to take down this new threat; Samus was dead.

The Rookie from Halo: ODST suffers from Post-Traumatic Vocal Disarticulation.
The Rookie's profile mentions that he became the sole survivor of the 26th Marine Expeditionary Force at the battle of New Jerusalem. In a similar vein to what happened to Lucy-B091 in Ghosts of Onyx, the Rookie remained fit for duty, and was then transferred to the Squadron, but the traumatic experience may have left him mute for the rest of his life.
 * Which raises the question of why he is still serving in the military. A soldier who can't communicate with his squad is not an effective soldier, and is liable to get himself or others killed.
 * Explain Lucy, then.
 * Super soldier.
 * She's actually not completely mute. She manages to talk in Halo: Glasslands. And she almost got re-assigned to ONI's psych branch after she lost her voice, but Kirk pulled some strings.
 * Nope. Your (if the above poster is the same as poster #2) philosophy looks to be "no matter how insanely skilled a soldier is, if they can't talk they're worthless". You can't say one thing about one guy who's suffering from a handicap, and then turn around and say the exact opposite thing about a girl who has the same handicap.
 * Though Lucy CAN communicate, to some degree. And Spartans don't really need to be very eliquent. Most of their battlefield communications are hand tics and status light flashes.
 * The Rookie isn't mute. He's just damn quiet.

The Gravemind changes from Halo 2 to Halo 3.
In Halo 2 he seems to be pursuing his own goals and speaks of being older at least than the Arbiter and the Chief- meaning he is far older than the current outbreak. Who could he have been feeding on? Before the arrival of the covenant and the humans, there was only the Forerunners. My theory is that as the flood changes the species it absorbs into flood forms, so too does the flood change. The Gravemind is the result of infected forerunners being absorbed, and genuinely wanted something other than just eating everything. So why does he change? After absorbing the massive numbers of covenant and humans he becomes less focused and more violent and so only desires to conquer the galaxy.

The ship that Master Chief's on will malfunction and it's jump drive ... thingy will 'port Master chief into Albion
Hal's armor in Fable 2 apparently belonged to a warrior who dropped to Albion from another dimension and was carrying an energy sword and assault rifle. Obviously MC had to change his armor in order to fit in which is why it looks like a Knight's armor and the sword has changed.

The multiplayer map Valhalla is literally Valhalla
The map description states that "The crew of V-398 barely survived their unplanned landing in this gorge...this curious gorge". That hesitancy about "this curious gorge" suggests an otherworldly location that does not behave as expected. Could it be that the crew did not survive, barely or otherwise? After all, an eternity of battling, being slain, and rising again for more combat the next day sounds an awful lot like matchmaking.
 * So it's not a play on Curious George at all then...? Hmmm... Your ideas intrigue me and I wish to subscribe to your newsletter.
 * The "curious gorge" line is a jab at how it's basically a remake of Blood Gulch. Except its a gorge, not a canyon.

The Rookie is mute due to an injury to his throat
At some point in the past (possibly even recent past), the Rookie suffered a serious war injury to the front of his neck, perhaps by a narrowly-dodged decapitation attempt by a sword-wielding Elite, or by a Brute trying to tear his throat out with its bare hands. Either way, the UNSC doctors were able to reconstruct his trachea ("windpipe") but the damage to his vocal cords was too much (or perhaps vocal cords are so complex or something that they can't be fixed that easily), rendering the Rookie mute. The rare grunts & groans we hear from him once in a while may be the only sounds his throat can make (the one time he whistles in a cutscene is due to the fact that whistling is - I think - unrelated to vocal cords). If it happened recently - say, shortly before the game - he may have even just been on a waiting list for a new cloned voicebox; perhaps he got it in the month between the game's end and the epilogue (of course, we didn't get to find out 'cause he was sleeping... again).
 * If that was the case, he'd have been given an honorable discharge, or at least put on medical leave. Even if the UNSC is desperate for men, a soldier who cannot communicate with his squad is a danger to himself and everyone around him.
 * ...Okay, I know the actual reason the Rookie doesn't talk is to "let the player pretend they're him". I'm trying to come up with a plausable in-universe reason, and after much deliberation this was the only one I could come up with.
 * But who says that The Rookie can not communicate, there are, today, researches on silent communication, mostly based on take the signals from the nerves that control the vocal cords and translating them intro sound. And even if this is not available there are silent ways of communication that special ops MUST know.
 * Jossed by the short story "Dirt". Unless the Rookie took a blow to the throat between leaving his last assignment and reaching Earth, it's highly unlikely.

ONI later gave the Rookie a job offer.
Dare was obviously impressed by him, and he definately has the potential. If you get all the audiologs, he actually figures out the truth behind the Superintendant before Dare does.
 * Maybe he was ONI Recon 111? (Heard on the H3 level "Tsavo Highway", when the Covenant Battlecruiser soars over your head) (Assuming my above WMG wasn't the case)

A final-stage Gravemind Rhymes on a Dime, all the time.
The ones we see only do it a little.
 * Sounds rather reasonable. Given how smart it is, and the love for poetry it has, it has probably the intellect to make great poetry with little effort.
 * Solidly confirmed by the short story "Human Weakness". Though, ironically, it prefers to make poetry BECAUSE it's more challenging than simply talking.

Halo and Assassin's Creed are set in the same universe
The pieces of Eden  were created by Forerunners.
 * Partly Jossed. ,
 * Well, if Those Who Came Before provided the original Hidden Blade design, they could also have provided the design for the mini energy wristblade thing that Elites have in Reach.

The Precursors are Pan-Dimensional beings.
If the Forerunners were the masters of the use of Slipspace, and the only ones that surpassed them in intellect and technology were the near-mythical Precursors, then their mastery must have been so great, they probably knew how to expand not only beyond the galaxy, or any point of the universe, but in entirely different universes.

The Forerunner crystal had the power to bend space and time itself. So, if Slipspace, with the adequate amount of energy and precise equations, could get ships in entirely different universes, then the Precursors' legacy has spread not only throughout the Galaxy (and having the Forerunner to create the "Mantle" legend to follow their steps as the protectors of sentient species), but throughout the universe... and other dimensions.

They might even have something to do with humanity. In the IRIS files, there is a map of Pangea. Is it a hint that the Precursors intended to have humanity become the rulers of the galaxy from the start?

Unfortunately, it might've also lead to the Precursors, and their descendants, finding the Flood before any other species.

The Flood aren't Pan-Galactic, but Pan-Dimensional.
Somewhat related to the previous theory. If the Precursors had actually fought the Flood at some point in the existence of their Empire, then the war against it is much, much, much older than anyone could ever imagine. If they fought with the Precursors of the Forerunner, then it means the Flood could've gained the means to cross through universes, with the technology stolen from them.

The Precursors may have found it in a world that had been fully consumed by the Flood, and with its' expansion into other universes, the Precursors may have had a phyrric victory in the fight in the fight against it (...or a complete defeat), and the Flood has spread throughout a few universes, and the HALO universe is one of many that had the tragedy of having to face the Flood.

And the reason the Flood came to the Forerunners, was because they were related to the Precursors (The Mantle), and had been chosen by the Precursors to rule the galaxy. After absorbing the Precursors, the Flood learned about the Forerunner, saw more absorbeable life forms, and knew that if they gained the ability to cross through universes, they could stand a chance against the Flood.

Without the means to contact throughout universes, the Flood has yet to see if they won.

Reach used to have a sizable Hungarian population.
Consider this: the moons of Reach are named Csodaszarvas and Turul, respectively, and it has a pair of towns/cities called Ezhtergom and Pálháza. Given these, it's likely that the first settlers included numerous Hungarians.
 * And they farmed food there. So the Hungarians were hungry.
 * All but confirmed. Most of the geographical features have Hungarian names, and you actually meet a group of them in the first mission. In fact, one of Noble Team is Hungarian and from Reach: Jorge.
 * Additionally, there are mentions of Reach cities bearing the names of Hungarian ones on Earth.

Master Cheif and Cortana are in orbit above the Forerunner homeworld.
Halo Legends drops some pretty big hints to this in Origins. For one thing, know we know that Forerunners were a different race entirely, and they had to recreate everything they annihilated with the Halos. They created cloning facilities for humanity, the species that would make up the Covenant, and presumably several of the more intelligent but still non-sapient animals. Logic dictates that they would've cloned themselves, but we don't see any. We also know the Forerunner planet is very blue, being primarily ocean and metal, which is similar to the planet Master Cheif and Cortana are stuck above.

My theory is that they're hiding on their home planet, watching the war from afar. They hide because they still fear the Flood, and rightly so. The Flood became a much worse threat than what Master Cheif ever fought once it got its hands on top of the line Forerunner tech. In the Halo games, it still got it hands on Covenant tech, but as said earlier, that's just a shoddy knockoff from Forerunner tech. The forerunners don't want to let their intellect be consumed by the Flood again, and so they hide.

343 Guilty Spark is still alive.
We see him being rebuilt in Origins, and it makes perfect sense. We know the Halo facilities can create infinite Sentinels, somehow, so logically there must be a place for Monitors to be rebuilt if they get destroyed.
 * [spoiler: Halo: Primordium]] certainly [spoiler: supports this theory.]]

Humans are the descendants of the Precursors.
The Forerunners discovered humanity on Earth, and they were genetically identical to the Precursor race. This certainly explains why the Forerunners were so interested in us as a species, and explain the quote "They hold the answers to our deepest mysteries" (spoken by a Forerunner about humanity).
 * This isn't really wild mass guessing, this is pointing out a widely accepted and heavily hinted at theory in the games. It's never outright stated, but so many hints are dropped that you might as well use an anvil.
 * NO! Read the wiki, or at least look at the Terminals in Halo 3. The Forerunners are explicit not humans. We were just considered more special than the other races.
 * Cept he didn't say Forerunner he said Precursor as in the guys that ruled but vanished before the Forerunners ever appeared on the stage. It's an interesting theory that would indeed explain the abnormal interest in mankind and why they were seen as worthy inheritors if there was indeed some connection to a race even older then them.
 * Theory seems to have been Jossed as of Cryptum.

The Forerunners created all the other races.
Including the Flood-- whoops! It explains why they're all humanoid and of similar mentality-- again excepting the Flood, who were a failed experiment Gone Horribly Wrong. They didn't save and replant the various species, just made new ones from scratch. The reason the Forerunners didn't "re"seed their own species was out of guilt over creating the Flood; or, they did seed themselves as humans or one of the other races and didn't want anyone to find out they're hiding in plain sight.
 * Nope, one of the Forerunners in the Halo 3 Terminals talks about documenting all the sentient races in the galaxy in case the Halo Arrays were fired. They might have had to clone new individuals, but they didn't create all new species. And, again humans are not Forerunner.

Humans are a Red Herring
. The reason the Forerunners keep saying that Humans Are Special is to distract everyone from the really important race-- the Grunts!
 * I knew their cuteness was just a distraction.
 * You ever seen them without their masks?

Buck and Sergeant Johnson will get at least a cameo in Reach
Or even feature in a cinematic, even if it's just a Funny Background Event. Or feature in a mission and fight alongside you. Just because it's Bungie's last game and it makes sense to do a Continuity Nod.
 * Half confirmed. Buck is never seen in person, but you hear his voice in-game in a side mission. Meanwhile, both his and Johnson's voices can be used in Firefight.

The ending cinematic or the bonus legendary cinematic will feature the Pillar of Autumn and Master Chief escaping Reach
Even better, they redo the opening cinematic of Halo in Halo: Reach graphics. Just imagine, the last shot zooming in on the cyrotube... Then it cracks open... 3, 2, 1-Game ends. Or for Serial Escalation levels, you get to play the entire first level redone in the Halo: Reach engine. What Do You Mean It's Not Awesome?
 * Sort of confirmed, a re-done part of the opening cinematic plays before the credits, but it's on all difficulties.

Place your bets on the Reach Big Bad final villain.

 * Evil Forerunner/Precursor
 * Mecha-Grunt
 * Human Defector
 * A young and spry Prophet.
 * Rogue Spartan
 * You sir, are awesome for reading that.
 * A giant fireball which you must escape from in a Warthog.
 * Waves and waves of mooks.
 * Destroying a Covenant carrier or supercarrier from the inside.
 * An arbiter
 * The Flood.
 * Answer:.
 * The Flood.
 * Answer:.

There will be a seventh member of Noble Team.

 * If only because of all the Magnificent Seven refrences that Bungie has thrown around in vidocs. Tying in with the above theory, he may or may not be evil.
 * There were actually originally were seven members, but the second default female SPARTAN soldier was cut and Thom was killed off, according to a Halo: Waypoint video.

If they ever make a game set after Halo 3 the UNSC will be the villians
While the games don't delve much into the subject the backstory paints the UNSC as an oppressive colonial empire. 50 years before the first Halo they nuked a rebellious colony into submission, the Spartans were originally kidnapped, brainwashed and experimented on to assassinate uppity colonists who thought they could run their planet by themselves and during the war with the covenant they've taken complete control from humanity's civilian government.

The ending to Halo 3 makes it seem like the war is turning in humanities favor and by the time Master Chief gets back from wherever he is the covenant might have been completely destroyed. Now which is more likely, the UNSC brass who have been given unlimited power for years quietly stepping down and letting a bunch of elected bureaucrats boss them around, cut their budgets and scrap their fleets to pay for reconstruction or them finding a new 'threat' to justify their existence? It was only a few years ago the elites were committing genocide against them and before the war they had been fighting insurrectionists for almost half a century. With how the backstory also implies the UNSC uses so much propaganda on it's population most aren't even aware of events offworld it's possible they could attack both and justify it to the masses.

My theory is that Halo 4 is gonna have Master Chief come back and find UNSC has turned on the elites and John * no reason to use his UNSC rank* fighting alongside insurrectionists and elites against marines and a new generation of Spartans to bring down the corrupt UNSC.


 * The Insurrectionists had a good deal of support back in the day. This was before they started using terror tactics (IEDs, kidnapping civilian starships, stealing nukes, etc.). While the UNSC could easily go military dictatorship, we won't be fighting on the side of the Innies. And we have no real idea what the situation in the UNSC was. It was created (and supported) by the Unified Earth Government, which would suggest that Earth held all the power, and the UNSC acted as its enforcer. The UNSC is really just the military and colonial administration.
 * Except the Unified Earth Government was as good as gone by the end of the war. Besides, 343 Industries is headed by Frankie. Logic dictates that due to most of Bungie being Firefly fans, he is. The Innies seemed to be expies of the Browncoats and the UNSC takes alot from the Alliance. So it's not too unlikely.
 * Jossed by Glasslands. The second chapter shows a new UEG president being elected.

A member of Noble Team will die before the campaign/story is even halfway done
As it says. Meaning, if there are 9 levels, Noble Team will be down one member by Level 5. If 12 levels, by Level 6, etc.

Noble-6 is actually AU Shepard
Both are completely customizable player characters who kick so much ass it is acknowledged by every person, as evidenced by Shepard's status as Spectre and Noble-6's classification as "hyper-lethal", which is alluded that even among spartans there is only one other with that rating (John). Also, then we can cross our fingers that Jennifer Hale could be the female Noble-6

Noble-6 is an Assassin
According to his/her dossier Noble-6 has singlehandedly broken up multiple organizations and made entire colonial militias vanish. Altair has killed at least that many by the end of Assasin's Creed. Noble-6 also falls from orbit and walks away from it with little more than a limp. The Master Chief at least needed someone to unlock his armor after such a fall. Six probably landed in the water and, like Ezio, didn't get hurt because of that. Lastly, is it only coincidence that this game gave you the ability to perform assassinations on anyone you happen to get behind in a fight?
 * Chief fell from a MUCH greater height, and Six had a pack specially meant for getting back into an atmosphere. It's only shown in a cutscene, but it explains how he survived. Plus, it's the fact that he has a knife that he can perform assassinations. We didn't have access to said knife in the previous games (but it would have rocked if we did!)

The UNSC has mastered Terraforming.
There is no other way Reach could have gone from "lifeless ball of glass" to "standard life-bearing world" by 2589 AD. Historically, when a planet has to create an ecosystem out of nothing but bare rock, it takes billions of years, not 35. This is backed up by the presence of a ship in the Pillar of Autumn's cradle, just visible in the far left of the shot: mankind has returned to Reach, and evidently they brought an ecosystem with them. (Amusingly, it seems to be a Halcyon-class cruiser, the same as the Autumn, despite Cortana describing the class as being mothballed. I hope that the ship shares a name as well as a home port with the Autumn.)
 * The UNSC has already mastered terraforming. Mars is blue and green, and Reach required a lesser degree of terraforming before it was suitable for human habitation. As a matter of fact, the Covenant do not possess the ability to completely glass a planet; it's propaganda spread by a secret Council of human AIs, in order to motivate their Creators in the fight against the Covenant. They're actually benevolent, but that's a story for another time.
 * So I suppose all the people that watched them do it in real time or could go out and look at the aftermath were all suffering from mass hallucinations then? The cinematic in the game itself showed huge sections of the planets surface apparently molten and visibly burning from orbit while a view at ground level shows a blasted hellscape of scorched rock devoid of visible life. I suppose that yeah technically they don't seem to have burned every square inch of the entire planet to a cinders, but it's pretty clear they were inflciitng a massive exinction level event resulting in global damage and climate change so it's getting into semantics really.
 * Actually, it's stated that the can't-completely-glass-a-planet assumption was made when the Council assumed that the Covenant Navy was the same size as the UNSC's, but it actually turns out that the Covvie Navy is several times larger than the humans'.

Noble-6 is just hiding.
We never saw the body and SPARTA Ns never die. 6 beat up the elites, left the helmet behind since it was busted, and, being so tired of all the senseless death, deserted (since nobody had ever seen 6's face, this was pretty easy). Halsey erroneously believes 6 to be dead.
 * I hereby call the posting troper as subscribing to a certain river in Egypt
 * UNSC's fantastically flimsy fabrication fostered from ONI files suppressing Noble-6’s survival.
 * To be fair, you never actually see the Elites run him/her through with a sword. It stops just before that. Enough time for a miracle to happen, I suppose.
 * Maybe Jun snipes them just before they finish off Six. It'd make for a good fanfiction.
 * This actually tends to happen in fanfic. If the writer wants Six to survive, Jun turns up at the last moment and saves him/her. Go, Jun, go!
 * Of course, there is Admiral Whitcomb, and his little band of collected remaining SPARTAN IIs still on Reach. Plenty of time to pull a Big Damn Heroes rescue between the Fall of Reach, and First Strike.
 * Whitcomb described the remaining SPARTANs on Reach as performing guerilla operations, so perhaps that explains all the dead SPARTANs lying around the Lone Wolf map; they were sent to extract Six, and got killed/drew the Covenant to Six instead. Also, is any of that fanfiction any good?

The Rookie is John Dorian from Scrubs.
His initials were confirmed to be JD, and the reason he never speaks is because he's intimidated, narrating internally and/or daydreaming. The "flashbacks" are all actually daydreams, too. "Upon reaching the top floor of the building, I noticed a strange helmet jammed really hard into a TV screen. What could have placed it there? Hmm..." *queue Buck sequence #1*

Cortana Was Behind it All--Part III
Okay, apparently the secrets Cortana deciphered from that "latchkey" discovery led to Halo, right? So why did Keyes think that they blindly jumped and just happened to exit slipspace near Halo? Because he never knew what Cortana was up to.

That said, it's apparent either Cortana's a very good actor, or she did not know the full story of Halo (there is no way she would've allowed Keyes to go to where the Flood were if s had the whole story). Since Halsey was certain what she had deciphered was humanity's only hope of beating the Covenant, it would suggest that they knew it was some type of weapon. Cortana seemed to know alot about Halo's purpose the very moment Master Chief plugged her into the control room; it's possible that she knew something of it's capabilities. However, her tone when she told the Chief that it "is not a cudgel", would suggest she had an idea it was an aimable weapon, rather than galactic death machine. Immediately after Chief returns to the control room, she is exceedingly pissed off. Perhaps it was all just because Chief had been following the Guilty Spark's lead, but she generally seems to be fairly patient with him; finding out that Halo wouldn't stop the Covenant without killing humanity is possibly the reason for her outburst.

So, then depending on how much Cortana knew, she could've either been The Chessmaster pulling the strings to ensure humanity's victory, or just a convenient Spanner in the Works on humanity's side.

The "Capture the Covenant leaders" mission was a cover.

 * The Pillar of Autumn's original mission was to steal a Covenant warship, fly it to their homeworld, kidnap their leadership, and negotiate a ceasefire. If you're thinking this is pretty stupid, that's because it is. The real reason for the mission was always to find one of the Forerunner's superweapons (Alpha Halo) and use it to defeat the Covenant. The timeline has the Spartans briefed on the mission on August 27; in Reach, Meanwhile, Keyes seems fully aware of just what  and Halsey/Cortana selected him for the mission on August 25. As for why the Spartans were told this, Halsey considered the information that secret. They were to be informed of where they were going once the Autumn had left Epsilon Eridani. Things never worked out the way they were supposed to.

master chief and cortana were saved
and not long after the end of halo 3, either. we know that the unsc spirit of fire was trapped out in the middle of literally nowhere, without a slipspace drive. we know that the chief and cortana were stranded in the middle of literally nowhere without the front half of their ship. i seem to rememeber some supplimentary materials putting the slipspace drive in the back of ships. maybye not all the time, but maybye. just think about it for a second. dosent serina say that something has happened after the credits on the legendary ending of halo wars? what if she was picking up the beacon cortana dropped? it is likely that she told the capitan, who sent marines to investigate. and probably the spartans as well. imagine their surprise to find, not only a working slipspace drive (well, sort of) cortana, and the chief. happy ending for all!
 * Jossed: Wars takes place twenty years before the trilogy.
 * That’s what the UNSC wants you to think!
 * The surviving cast of Wars goes into cryosleep at the end. It's possible that they just stay that way for twenty years until meeting Chief. Selena picking something up at the end could've been a fast forward.

Sergeant Johnson being immune to the Flood is not a fluke.
At some point while investigating some Forerunner stuff, the Earth government discovered either records or preserved remains of the Flood. Realizing that this will likely become a problem later, they included an immunity to the infection forms in their supersoldier programs. They didn't give mass injections either because they believed their super soldiers would be the first to encounter such a threat and that would give enough time to give mass inoculations or because producing the "vaccine" is very expensive and difficult. By the time they discovered the Flood were out there on a large scale and actively expanding, they no longer had either the time or the to give the treatment to enough people for it to matter.

The soldiers on the autumn are NOT marines
The soldiers in combat evolved are primarily UNSC Army from reach, not marines. Look at the color of their armor, it looks like a updated version of the H:CE soldiers. Bungie clearly retroactively retcon the autumn's soldiers to be army instead of marines. Notice the soldiers guarding Keys are army soldiers.
 * Actually, if you watch you can clearly see them wearing the Halo 2 and 3 style marine armour.

The rookie CAN talk
However,he never does due to the fact that he is asleep in the first and last cutscene, his transmitter was likely busted in the crash (which knocked him out for hours)and once he does get to Dare, when he does get a few seconds that he can speak, he don't because, lets face it, you are going to take a LOT of hits while scouring around rain drenched new mombasa, and are likely running solely on whatever the hell is in those medpacks.
 * Alternatively, he does talk, but you can't hear him- you're supposed to fill in his dialogue yourself.
 * Confirmed by the short story "Dirt". The Rookie not only talks, he does it quite a bit.

The Forerunners have interbred with humans.
They're apparently very similar, and there seem to be few biochemical barriers in Halo, so it's possible. Also, it would explain why the Forerunners are referred to "forefathers" of humanity; most humans have a Forerunner ancestor somewhere. Which is why humans are "reclaimers" in the first place.

the precursors are the flood.
or, atleast, due to the fact that the precursors seemed to have extra-galactic travel, they may have found the flood in a nother galaxy, and that galaxie's local gravemind sent a few flood spores over to take over this galaxy.
 * According to Primordium, that theory is

Eventually, 343 Industries will let you place bots in Forge.
Forge 2.0 in Reach is significantly more advanced than the Forge in 3, and Bungie has even stated that players are using the same tools that the developers use to make maps. It's only a matter of time before you can start placing bot paths and Grunts, Elites, Jackals, etc., allowing you to make your own mini-campaign level. Of course, you'd need to work to make it good, but think of the possibilities: one Warthog and a tunnel filled with baddies, ascending a Covenant-controlled tower, Spartan-Jackal sniper duels, a Multi Mook Melee in Blood Gulch, all made by you.
 * Only if they figure out how to do it without burning out the console...

343 industries will remake halo 2 and three, together, as an ubergame, as bungie had originally planned.
i cannot wait to see the forrerunner tank level...

Cortana did not choose the Master Chief because of his "luck".
She said that he had one thing no other Spartan had, but it wasn't luck. It was just his "hyper-lethal" rating, and his having the highest rank. Statistically he was the best choice, so she chose him over Noble Six. she even has Six escort her to the Pillar of Autumn, indicating Cortana's preference for hyper-lethal spartans.
 * Which, on it's own, makes sense.

The Flood are the result of a semi-biological AI that went Rampant.
The description of an AI in the Jealousy stage of Rampancy (where it begins to consume as much information and as many as possible) sounds exactly like a mechanical/digital equivalent to the Flood. This is supported by Mendicant Bias' corruption by Gravemind by the later convincing the former that they were similar. Perhaps the Flood were created when a Precursor AI (can't be Forerunner since the Flood predate them) found a way to create a biomechanical computer system for it to inhabit, giving it the capacity of an organic mind but with the organization of a digital computer (something like Mother Brain). Eventually, after enough miniaturization, the computer's "cells" could have evolved into flood super cells and the original system would have become the first Gravemind.

The series is a metaphor for U.S politics.
With humans representing the Republicans, the The San 'Shyuum representing Caucasian Democrats, The other species of the Covenant representing minorites and
 * This makes NO SENSE AT ALL.
 * it makes perfect sense

The Reapers were created by the Forerunners.
As the 300 year war with the Flood dragged on, the Forerunners decided to create an entire fleet of A.I. guided warships, in the hope it would be immune to the Flood's traditional assimilation strategies. Problem: when the Reapers started calculating the odds, they decided the galaxy was doomed and that the only safe refuge was another reality altogether. They managed to escape to the Mass Effect universe, but whether by chance or design it was several million years before even the Forerunners rose to power. The Reapers, paranoid that the Flood might follow them, decide that the only way to ensure their safety is to make sure that no organic race ever comes close to matching the Forerunner civilization. This is why they created the Mass Relays and the Citadel: galactic society evolves along lines they choose, is easily culled and in the event that the Flood do manage to hop dimensions, cutting a Mass Relay will isolate the infected area and allowing for quick sterilization. Thus, the Reapers maintain an image of mechanical godhood in order to hide the fact that they are completely terrified that the Flood might track them down.
 * Ah, yes. 'Reapers.' The immortal race of sentient starships, allegedly waiting in dark space. We have dismissed that claim
 * We learn in Primordium that

The Needler is a Railgun
The crystals used in it can conduct electricity and are natural capacitors, making them, not only the ammo, but the battery. This can also (or maybe not) explain why the needles explode when enough of them are on a body, they discharge the energy at once,killing the target, and explode because of the feedback

Master chief is Kai
This is why he's such a smart ass to cortana,and why his suit looks like a guncannon.

343 Studios' new Halo Trilogy (4 through - presumably - 6) will feature something directly connected to the Precursors (Those Who Came Before the Forerunners)
'Cause, come on, they're mentioned all over the Expanded Universe stuff. Also, Halo Waypoint says Master Chief will "face an ancient evil that threatens the entire Universe". Maybe an old enemy of the Precursors... or maybe the Precursors themselves...

Sergent Johnson is Dead
And had been since the beginning of the first game, where he was killed by the Covenant. So why is he present later in the game? Think about it: he survives several things normal humans cannot, like the Flood and the explosion of a Halo. How? He is a hallucination by Master Cheif! Obviously, John and Johnson were good friends prior to the events of the game, and John simply couldn't take the fact that his best friend died. So he began hallucinating him everywhere, and came up with unlikely solutions such as him being immune to the Flood virus and him being on the Pelican he later linked up with. The ending of the third game either (a) is symbolic of John coming to terms with his friend's death, and imagining it happening then to reconcile with his old memories, or (b) is irrelivent because John will simly imagine him having survived later. Why do other characters interact with Johnson? Because Cortana knows about the halucinations too, but also knows that Johnson is the only thing keeping together John's scarred psyche. She "aids" the illusion a bit with handy voice synth and a few key holographic projections. He leaves at key points in the story because Cortana knows she and John will need their full concentration and therefore she tricks John into beliving he's left. The reason we meet Johnson in Arbiter's level is because the Halo story is told from Master Cheif's perspective and he fills in another character in Arbiter's stories with Johnson. The story being told from John's perspective is also the reason for the wide fandom possesed by Johnson: he was John's favorite "character," too. All of the enimies killed by Johnson were either (a) killed by the Cheif himself, (b) never there in the first place, (c) Cortana's projections, or (d) in reality killed by someone else, possibly someone the Cheif is seeing as Johnson. In short, all of the events of the game involving Johnson are either a hallucination on Master Cheif's part or his recounting of the Arbiter's stories and inserting Johnson, and Cortana plays along and seals possible "cracks" in the illusion.
 * So...Johnson is MC's personal Reznof? Someone's been playing to much Black Ops.

At some point in the new trilogy, Master Chief will have to go back in time
Just like the security officer in Marathon, John will royally endanger the fabric of space and time. This may involve uncovering horrible secrets beneath the Human and Covenant war, the artificial intelligence constructs, and Earth itself. More importantly what reason to why he still lives.
 * To explain:
 * The Spartan IV program could actually be an immoral resuscitation program for recycling fallen or comatose soldiers.
 * Master Chief could reveal he had lost most of his humanity and was in fact more machine, thus going rampant.
 * A 'big mistake' he made might go back all the way to his awakening on the Autumn, he'll revert to that period of time and kill captain Keyes in part of his rampancy
 * Towards the end of rampancy, he becomes something more akin to a god-like being

The Precursors killed the dinosaurs.
Hey, if the Forerunners were apparently able to devolve us so we forgot about them, the Flood, and our previous culture, who knows what the Precursors did around the galaxy before then?

The reason the new version of Halo: Fall of Reach listed the Covenant fleet as 700 ships
That quote from Lord Hood in Halo 2: "The fleet that attacked Reach was 50 times the size of this one." The fleet he's speaking of consisted of 14 ships. Multiply 14 by 50 - you get 700. Could also be because of their fetish for 7

Mendicant Bias's "Atonement"
If you've read the last Terminal in Halo 3 on Legendary, you saw that Mendicant Bias claimed he would "keep the path stable". I'm sure we've all assumed he meant holding together the Halo when it was being fired or fending off enemies offscreen, but what if the "path" is the Portal? I believe that Mendicant Bias "set" (or programmed, or whatever) the Portal to drop the Chief off at the Forerunner world we saw in the Legendary ending and the beginning of Halo 4. Which leads to my second WMG, that...

... We're Going to See Forerunners in the New Trilogy
Read the above WMG. In the last Terminal, Mendicant Bias stated you would be an example of his change of heart for his former masters to see. But how would the Forerunners know of his atonement in saving Chief? Because, if he sent Chief to that Forerunner world, as I stated above I believe he did, he must have known that Forerunners would be there to find Chief and learn of his attempt at atonement. What do you think?

The Secret to Defeating the Flood
In Halo: Cryptum, we learned that ancient Humans discovered how to destroy to Flood. A geas was placed on Chakas which would eventually uncover said secret. However, since the Forerunners had to activate the Halos, we can assume that they never found out said secret. But in the new Forerunner Saga book, Primordium, Chakas appears to be conversing with the "last Reclaimer". Now, here's what I think: in the new Reclaimer Trilogy, the galaxy will face a resurgence of Flood, possibly with extragalactic origins. Chief will find Chakas, learn the secret, and permanently wipe out the Flood. What do you think?

The Rookie's last name is Dante
Considering that there is a lot of symbolism in ODST refering to Inferno, this one actually has a lot of weight. We know that the Rookie has the initials J.D.. He's led around by an AI/Engineer thing named Vergil. The audio logs, which the player finds, subtly refer to the Seven Deadly Sins, and karmic punishments for them. Add this up, and the odds of the players name being Lance Corporal Jonathan Dantes (or some other J name) gets much higher.

Call of Duty takes place before Halo

 * Years before the games main setting, the events of the Call of Duty series happened, this could explain the downgrade in game perspective, and it could still be true book wise (which the halo weapons are far more powerful than modern and their game counter parts.) but with out a downgrade side effect.
 * Technically that's true by default as all the Call of Duty games before Modern Warfare were based on real life events, and real life events are considered canon in Halo as it's 500 years in the future, and it's not farfetched for the Modern Warfare games to be in there, at least not until the 22nd century, where by Halo canon explicitly states Earth formed colonies in space.

Either John or Lord Hood will be involved in rescuing Halsey from Paragonsky.
Think about it, three of Halsey's Spartan Twos saw her get kidnapped in Glasslands, and had some major issues with it. Imagine how John would feel. One of the Spartan Twos is going to tell Lord Hood, and he's going to find where she is and either send a Spartan II or John (If he gets back to UNSC Space) to rescue her. Or perhaps I am just doing some wishful thinking.

The Didact will be the main antagonist in Halo 4, and perhaps the entire Reclaimer Trilogy
From what I understand, The Didact is able to possess other Forerunner, as he does in Halo: Cryptum. Who's to say he didn't cryogenically freeze other Forerunner or shield some in a Forerunner shield world for that very purpose? He could jump from body to body. Also, Halo Combat Evolved Anniversary's terminals were confirmed to be related to Halo 4, and in the last in-game terminal, 343 Guilty Spark talks of

The Spirit of Fire and its crew will play a part in the Reclaimer Trilogy
With the loss of the studio who made Halo Wars, an actual sequel seems extremely unlikely. However, there's nothing stopping the SOF and her crew of badasses from making appearance in future games. Perhaps the Forward Unto Dawn won't be the only drifting, driveless, Human Popsicle-carrying ship to get drawn in by the Forerunner Planet?

Halo takes place in the same universe as Warhammer 40000and Warhammer 40000 is a "prequel" to the Halo series
Why? There was once an Ancient human civilization that achieved a considerable level of technological sophistication, achieving interstellar travel and conquering many planets. They apparently declared war on many alien races they encountered. You might ask: How? Wasn't the Imperium of Man besieged from all sides in WH40k? The thing is here that the final downfall of the Imperium occurred 10,000-20,000 after WH40k. It is quite possible that The Emperor was revived as a "God of Order"(perhaps by the Star Child theory) at the end of M42 and was able to beat back Chaos following the "Time of Ending", ushering in a new era for humanity. However, in this final battle, most of the original races of the Galaxy were destroyed, leaving room for others to evolve, and the Imperium loses most of it's territory. Therefore, with the help of the God-Emperor(and perhaps the revival and return of the Loyalist Primarchs as well) as a presence in the War, they were able to rediscover old technology and go on a second "Great Crusade". However after another 10,000 they were destroyed by the Forerunners, which destroyed all knowledge of Warp Travel after their defeat, which is why neither the Emperor or Chaos have any impact on the Halo Universethey were totally cut off from this plane of existance.

Chief will warp back to a universe where Cortana never was created
All intelligent life will be, at the least one-hundred seventeen years behind in technology. Compared to the current one which lay in ruin. John 117 will be in cryostasis on board a woefully outdated "Marathon Class Cruiser" with no name. This'd be Halo 6's story beginning by the way. Well the Covenant board and Keyes, whom is much more lean and simple, muses on how their enemy was always quicker. Characters such as Cortana and all monitors no longer exist. As if humanity wasn't there yet, technologically. Halo is more of an incomplete ovular ring, resembling Forerunner technology at third lowest stage in advancement. Its surface is one seemingly endless city, similar to those seen throughout Bungie's Marathon series. John is well aware that gods (precursors) had gave intelligent life another chance. Eventually he finds out the Flood never happened in this dimension, and that Halo's real purpose (Parallel universe, mind you) is to preserve life when billions of years pass by closing everything.