New to Halo and need to jumpstart your way in? Long-time player of the games and completely lost by the story? Maybe you even think you’ve got a good handle on the wider story and just want to make sure. Well, here’s the complete summary of the game plot and all of the supplemental material to give you a more complete understanding of the Halo universe.

As usual, we eagerly welcome any feedback you might have for us, such as additions, changes, and especially any sections that could be streamlined further.

Note: This is the ultimate spoiler of everything ever, as it takes the pieces from all the games, books, movies, etc., and strings them into one continuous narrative.

All images are from halo.wikia.com unless noted otherwise. 

In the Beginning

Our (relatively) quick jaunt through the Halo universe starts nowhere near Master Chief. Instead, it starts hundreds of millions of years ago, with a race of huge, trans-sentient beings able to create life themselves, called the Precursors. They created the Forerunners, but as typically happens with ungrateful subjects, they were betrayed and eliminated by the Forerunners millions of years ago. The Precursors left a parting gift, however: tons of glass jars of fine powder of unknown origin and composition, which eventually turned out to be the stuff that created the Flood. Which, as things turned out, was a pretty effective revenge gift.

The Main Thing to Understand about Halo is the “Mantle” of Responsibility

Forerunner civilization revolved around the concept of the Mantle, a galactic White Man’s Burden or Mandate of Heaven. Citing their victory over the Precursors and galactic hegemony, the Forerunners believed that they were bequeathed this responsibility. Presumably, eventually the Forerunners would lose the Mantle as well and pass it on to someone else, although they were neither exactly clear on when nor very accepting about letting their civilization be subsumed. The Forerunners inherited the ability to create and shape life, and did so on lesser species to minimize conflict.Keep the Mantle concept in the back of your mind, it’s important in realizing various characters’ motivations.

Here humanity enters the scene. Sort of. Humans did exist 100,000 years ago. Unlike us, early humanity was actually awesome, and had technology and power that was comparable to the Forerunners, mainly by gathering and reverse engineering Precursor tech. One such mission led to the discovery of a crashed ship containing tons of cylinders with a white powder inside. With early testing supposedly revealing it to be harmless, we began to test it on what essentially amounted to pet "spacedogs" because it seemed to give them desirable traits. However, this eventually led to the spread of the powder, otherwise known as the cells that form the Flood. With these pets coming in close contact with humans, the Flood cells were able to infect humans as well, causing the creation of the warrior form Flood you might recognize from the games. The threat of the Flood then began to increase exponentially, so like the barbarians that attacked Rome because the Huns were breathing down their necks, we moved into space occupied by the Forerunners, who retaliated, forcing humans to fight a two front war.

In the face of such opposition, humanity actually more or less rose to the challenge. Realizing that the only way to stop the Flood was to kill off its food supply, the Human government genetically altered 1/3rd of the Human population with genes that fought off the Flood biomass. They then effectively feed these humans to the Flood to try and stop the spread. It was super effective! In fact, it worked so well that the Flood were nearly decimated and had to retreat. However, the Flood had taken their toll, sapping Humanity's strength and their ability to fight.



One of the early advanced humans

The Forerunners pressed us back to our capital city, and even though we held for 50 years, on account of it being like Minas Tirith, we were finally beaten. Most of us committed suicide, and the Forerunners pulled a Rome, forcibly devolving us back to cavemen and destroying any evidence that we were ever that cool. By the way, our closest allies in this war were the Prophets. Yeah, you know, those weak anorexic guys that called for our elimination in Covenant times. I guess they were still bitter.


History is written by the victors

Suddenly, Flood.

So now the Forerunners are sitting pretty right? Actually no. Already really weak and complacent after dealing with us, they got blindsided by the Flood. Again with the Rome analogy, the Forerunners had no idea that humanity was fighting so hard because we were actually running away from the Flood. At first, the Forerunners tried with simple conventional warfare, but battlefield casualties added up for them doubly: men they lost became enemy combatants.Give the Forerunners credit: they really did try everything imaginable, and ultimately their desperation led to them destroying entire star systems in a form of scorched earth warfare.


Forerunner ships combine power to obliterate the planet surface

Finally they began building the Halo Array, a group of seven giant rings that, when activated, sync up series of radioactive pulses simultaneously across the galaxy, killing all sentient life and thus denying the Flood any more sustenance and starving them to near extinction. The array is controlled by the Ark, which as its name suggests, is safe from this destruction because it is located just outside the Milky Way.


The Ark deploys the Halos

Dramatis Personæ

Did the Forerunners have political problems and intrigue like us? You bet. Just on a galactic scale. The Forerunner’s commander-in-chief was a guy known as the Didact… yeah that guy who’s getting all the press from Halo 4. He led the warrior class of Forerunners called the Prometheans. He fundamentally believed in the Mantle and the Forerunner’s responsibility to uphold it; thus, he opposed using the Halo Arrays because that would be abandoning all the little defenseless species that depended on them, instead proposing his pet project, the Shield Worlds, as ways to strike at the Flood from safe strongholds. This brought him in direct political conflict with the Builders, who were the main faction supporting the Halo solution. He lost, and most of his supporters exiled or killed themselves.

His wife was called the Librarian, because she had the glorious job of indexing all known species, document them, and save them by moving them to the Ark. Probably not two of each kind. Because then the gene pool would collapse. Or because of animals like pandas, which take a lifetime and a half to even get a baby, then accidentally sit on them. 


Anyways… she caught the Didact one day using this handy machine called the Composer, which is designed to digitize organic life. He was doing it to Prometheans so that the Flood would lose that +1 advantage described earlier. Thing is, he was also digitizing humans, with the ultimate goal of digitizing ALL humans as cannon fodder to throw at the Flood.


The Librarian did not like this at all. She was in charge of the Ark's other function, cataloging the sentient species of the galaxy and preserving their genetic data so that they could be reseeded once the Halo's had fired. And though the Didact was her Husband, she incapacitated him and threw him in jail, which looks like a giant ball, and hid it in the Shield World called Requiem. In the final days before the Halo firing, she went behind enemy lines, to Earth, and built a portal to the Ark and buried it. She believed the Mantle will fall/had fallen to humanity, because her husband’s stubborn belief that the Forerunners still possess it had only lead to the deaths of billions that they supposedly had an obligation to protect, not to mention his willingness to use humans so expendably. This is the reason humans are referred to as “Reclaimers.”So we kinda owe her. A lot.

Finally, the Forerunners activated the Halo array and were presumably all wiped out, after which, automated ships returned species stored on the Ark to their respective homeworlds. 




Fast forward awhile, because the intervening time was just evolution taking its sweet time. In 938 BC, the Prophets and the Elites came in contact with each other and began fighting over Forerunner ruins. They fought each other to a stalemate and began to respect each other, so they formed an alliance, or “covenant,” if you will. The Elites agreed to protect the Prophets while the latter discovered and researched Forerunner artifacts. This is how the Prophets became the scraggly and frail wisps they look like in the games; too much sitting around and eating chips over millennia. They used to be able to spar with Elites, and now look where they are. After you’re done reading this, get outside for a while!

Over time, additional races were converted and added to the growing hodgepodge that was the Covenant, generally because they had to at gunpoint/threat of extinction. All of them were expected to pitch in their talents toward the ultimate goal of the Great Journey, the Rapture or Judgment Day of Covenant religion. The Covenant believe that the Forerunners created a way to become trans-sentient by activating the Halo array (Sacred Rings). However, the actual belief that most races have towards these doctrines varies greatly, with many members believing out of convenience or fear, not piety.

Duty Roster

A quick laundry list description of the various aliens in the Covenant, the “actual” name is frequently used in the books, generally in the order they joined from first to last, can’t exactly be sure.

Prophets: (San’Shyuum) perfidia vermis: religious and political leaders, obsessed with finding Forerunner relics and start the Great Journey, founding partners of the Covenant


Elites: (Sangheili) macto cognatus: military leaders and main fighting force, society based heavily on tradition, respect, honor, and the demonstration thereof, other founding partners


Hunters: (Mgalekgolo) ophis congregatio: actually a giant cluster of worms working in unison, not a single form, the first to be added to the Covenant, very quiet and antisocial


Engineers: (Huragok) facticius indoles: made entirely from scratch by the Forerunners, tech and engineering geniuses, created with the express goal of maintaining Forerunner infrastructure, although their natural curiosity means they will maintain and upgrade other things as long as it doesn’t interfere with goal #1


Grunts: (Unggoy) monachus frigus: cannon fodder, laborers, unintelligent, cowardly, come from a cold methane homeworld, generally serve out of fear not devotion, occasionally have mass uprisings like Russian peasants, about as effective


Jackals/Skirmishers: (Kig-Yar) perosus latrunculus: used for recon and sniping, often carry a physical energy shield, generally serve more for money than devotion, used to be/ returned to being space pirates


Drones: (Yanme’e) turpis rex: flying bugs, used as mass cheap airborne infantry, used as engineers on ships when Engineers aren’t available; they resent this greatly, follow orders blindly; hive mind, view the Prophets as “queens”


Brutes: (Jiralhanae) ferus servire: latest addition, giant ape like creatures, have a huge rivalry with the Elites, never advance b/c they always blow their achievements up in civil war, now totally devoted and believing converts, very primitive in nature


What about Us?

Yeah, what have we been up to this whole time? Well you know most of the story, it’s just the part in the next few centuries that might be a little confusing and the most implausible. Somehow, the UN managed to get all of Earth’s silly squabbling countries together under a group called the Unified Earth Government. It wasn’t easy, and a major war was fought in our solar system, but they got it done. This is why I think we’ll never have nice things. Think about it, we only get FTL travel and an interstellar empire AFTER everyone decides to play nice at home. Mass Effect is the same way. What is much more likely to happen? Fallout.

So the main military force of humanity is the United Nations Space Command (UNSC), which is much more effective than current UN forces. (Marines’ performance in the games notwithstanding) From the end of the 2400s to the mid-2500s, as tends to happen, colonies on the outer periphery of human controlled space begin to rebel, in a movement called the Insurrection, whose members, known as Innies, resorted to terrorist tactics. A common joke was that it was funny how much the Innies wanted out.


If only the actual UNSC had such a cool emblem 

After a few decades, casualties were mounting, especially for the UNSC, with no clear end. I mean, look at how hard it is for us to regulate air travel on one planet, and how frequently that fails. Now imagine that extrapolated to dozens of PLANETS. Soon the rebellion would require a huge military operation to have any chance of being put down. So a scientist named Dr. Catherine Halsey put forward a bold plan. Really quickly, most of this cloak and dagger and pretty illegal stuff happens because of an organization called the Office of Naval Intelligence, essentially the new CIA.


ONI's emblem... how cloak and dagger

Halsey proposed that the UNSC create supersoldiers, which became known as the SPARTAN-IIs. Budget cuts halved the planned number, so 75 candidates were selected at an early age for superior mental and physical shape, and abducted from their parents to begin training. In addition to incredibly rigorous mental and physical training from six years of age, when they were 14, they underwent a series of physical “augmentation procedures” which went beyond tons of steroids, and included grafting composite resin onto bones for strength, boosting eye blood flow, and accelerated growth hormone treatment, to name a few. 30 died outright and 12 were irrevocably crippled. The able survivors were paired with a powered exoskeleton called MJOLNIR. Various cool sounding technologies amplified the soldiers’ abilities even further, although no one could use it except for SPARTANs; only reinforced muscle and bone can handle the speed and force increase. Master Chief Petty Officer John-117, is the most well-known of this group. They were initially deployed against the Insurrectionists, to great success. And then the Covenant showed up.


Fun stuff...  (ign.com)

Are We There Yet?

Yes. This is where the Halo games actually start showing up. I know, crazy right? We’re eight pages in already. In 2525, a Covenant ship raided a food transport, and humans set off a response ambush. Then the Covenant came back in force, looking for Forerunner relics on the planet Harvest. (the "relics" actually were the humans themselves) A skittish Grunt shot at a militiaman and that was the shot heard ‘round the galaxy.' After this, the Prophets realized that we were the successors to the Forerunners, but telling everyone that would pull up the curtain on the charade that was their entire religion. So instead, they declared humanity to be heretics, defiling Forerunner holy sites, and ordered a complete genocide.

Immediately the disparity was clear, both in terms of man/alienpower and technology level. Covenant fleets and ships were massive, and had advanced plasma weaponry and energy shields, while we were more or less stuck with small tin cans and tiny missiles. Also, the Covenant didn’t even need to launch ground invasions; once the space defenses were obliterated, ships overhead “glassed” the planet; energy beams turned the soil into glass on every square inch of the planet. It’s also kind of hard to evade your enemies when you yourself are a homing beacon; they had instruments capable of detecting Forerunner relics, aka humans. In an attempt to take back Harvest from us who took it back from them, the Covenant found information leading them to a Shield World, which a Spartan II team followed. A guy sacrificed himself, the Arbiter was killed, and the Shield World destroyed. That was Halo Wars in two sentences.


The Shield World in destruction... marking the start of a theme of planetary obliteration

It’s 2530 and we’re losing badly; OK, to be fair, we were losing badly from minute one. But as effective as the Spartans were at wrecking the Covenant, there simply weren't enough to be everywhere at once. Also, they were dying, a few at a time, here and there, and it adds up. Moreover, the myth had already been created of Spartans doing ridiculous things, like never dying. They were only listed as MIA or WIA. But what that ultimately means is, we had to rely on MARINES. God, no wonder we were doing so badly. We needed more, and we needed them fast and on the cheap. So this guy named Colonel James Ackerson came up with the SPARTAN-IIIs. The candidates were mostly pissed off orphan kids from lost colonies, the augmentation was going to be less costly, both in dollars and lives, the lengthy training shortened, the MJOLNIR armor tossed out for something much cheaper. 


The SPARTAN-IIIs would be trained in groups of 300, (ah, I see what you did there, Bungie) and sent on guaranteed suicide missions. They were the Big Mac to the SPARTAN-IIs’ 10 oz. dry aged Angus filet mignon. Two full groups were successfully used in several different major surgical strikes deep inside Covenant territories. There were only two survivors. However, through efficiencies of scale, ONI believed they would be able to increase that production significantly to maybe a hundred thousand in a decades’ time. Until their secret training base gets invaded by the Covenant. And Dr. Halsey shows up in a hijacked ship with a kidnapped SPARTAN fleeing from reach. Most of the company are already gone, leaving a group of maybe 25 SPARTAN-IIs and IIIs. They come to the realization that this planet is actually just the outer coating of a Shield World, and they take the portal inside, sealing off the Covenant outside, but also trapping themselves. After a considerable amount of time, they found an Engineer, which allowed them to send a transmission out, and were rescued, and Dr. Halsey was promptly arrested for hijacking the ship and kidnapping said SPARTAN.


A UNSC installation on the surface of the Shield World Onyx