Forerunner

"After exhausting every other strategic option, my creators activated the rings. They, and all additional sentient life within three radii of the galactic center died, as planned."

- 343 Guilty Spark, explaining the fate of the Forerunner.

The Forerunners were an ancient race of enlightened beings whose empire -- known as the ecumene -- encompassed three million fertile worlds in the Milky Way Galaxy approximately 100,000 years ago. "Forerunner" is a literal translation of the species' name for themselves; they identified themselves as such because they believed that they held an impermanent place in the universe's Living Time and that they would be succeeded by other, better races. The Forerunners were the creators and builders of many significant installations, including the Halo Array, the Ark, and the Shield Worlds, as well as numerous lesser artifacts later found on many worlds. The Forerunners were preceded by another, even more powerful race, the Precursors. The alien faction known as the Covenant worshiped the Forerunners as gods, deriving much of their technology from Forerunner artifacts found throughout the galaxy, and believing any who defaced these relics to be heretics.

Known history
"The Forerunners were a wise, highly intelligent, noble people, and with a belief in justice, in peace, they bravely faced the adversary. They sought to sterilize it."

- Cortana on the Forerunners.

Origins
The Forerunners were a very advanced civilization, coming to power after the disappearance of another race, known to them as the Precursors. Unbeknownst to the Forerunners as of the year 100,000 BCE, the Forerunners had been created by the Precursors, and millions of years earlier had overthrown and destroyed them, leaving only one in permanent containment on Charum Hakkor.

The Forerunners originated on the planet Ghibalb in the Orion complex. The world served as the hub of the Forerunners' fledgling interstellar civilization until it was rendered uninhabitable by an astroengineering disaster. The Forerunners had attempted to manipulate several stars in their region of space, but accidentally caused a series of supernovae that resulted in their planet being burned to a cinder by radiation. Early on in their history, the Forerunners controlled a total of twelve significant systems; these would later have symbolic importance. The Forerunner civilization rose to preeminence in the galaxy in roughly 150,000 BCE, around the same time humanity first began moving its interstellar civilization away from their homeworld, supposedly to escape early Forerunner control. The capital, the center of the Forerunner ecumene, was constructed around 225,000 BCE.

The Forerunners reached their peak before activating the Halo Array around 100,000 BCE, in the closing days of the Forerunner-Flood War.

Human-Forerunner war
Around 110,000 BCE, the Forerunners went to war with humanity's interstellar empire, in response to a perceived invasion of new colony worlds. This invasion was thought to be caused by both human resentment at Forerunner expansionism during the previous fifty years and by the rapid growth of human populations. After the war, a small number of Forerunners discovered the true cause of the invasion: a desperate human migration away from a extragalactic parasite known as the Flood. Desperate for new, uninfected worlds to replace the ones lost to the Flood, humanity invaded the worlds of other civilizations, bringing them into direct conflict with the Forerunners, who saw themselves as protectors of the Mantle. The Forerunners perceived humanity's actions to be a threat to the principles of the Mantle, and therefore waged a decisive war against humans, subjugating every human-controlled world and wiping them clean of all traces of human civilization. As punishment, humanity was stripped of its empire and technology and was exiled to its homeworld, Erde-Tyrene. There, humanity was devolved into a number of subspecies and forced to begin anew. The Flood, meanwhile, had been pushed beyond the edge of the galaxy by humanity's military efforts, and all traces of its existence vanished.

Following the events of the Human-Forerunner wars, a select group of Councilors and other elite Forerunners turned their attention to the possibility that the Flood would return. The Didact advocated a policy of watchfulness and military readiness, and proposed the construction of a series of Shield Worlds to provide quick military support should the Flood reappear. However, this plan was overruled by the council in favor of one put forward by a faction of Forerunner Builders, who proposed the construction of an array of galaxy-sterilizing super weapons as the ultimate defense against such a threat. These proposed weapons would be designed to starve the Flood to death by killing all sentient life in the galaxy with enough biomass to sustain them. The council's acceptance of this plan caused the Librarian, a prominent Forerunner Lifeworker and the wife of the Didact, to speak out in condemnation of the Builders' proposal of mass genocide, and as a result she and other Lifeworkers were permitted to work on the project as well, integrating their own measures for preserving the galaxy's life into the plan. The plan, the Library Project, resulted in the creation of the Ark and twelve massive ring-shaped installations known collectively as the Halo Array. Meanwhile, the Didact and the other Prometheans who had supported his cause were removed from the council and executed or exiled. The entire Warrior-Servant rate would be marginalized over the next thousand years, with their fleets and armies disbanded, leaving the Forerunners ill-prepared when the Flood would re-emerge.

Forerunner-Flood War
Roughly nine thousand years after their war with the humans, a Forerunner survey team to the planet G 617 g came into contact with the Flood. After this first contact, the Forerunners immediately recognized the great danger that the Flood posed to the entire galaxy and attempted to contain them. Even though they knew the power of the Flood, the principles of the Mantle forbade them from destroying it. As such, the attempt to contain the Flood was a failure, as they tried methods more suited to disease control instead of all-out warfare, trying to contain and quarantine the Flood rather than attack and destroy it outright. They did not start war until it was far too late.

When the Forerunners were unable to contain the Flood outbreak, the galaxy entered a state of war. During the 300 years of the conflict, the Forerunner studied the Flood in labs such as the gas mine located in the atmosphere of Threshold, looking for any exploitable weakness. As the Forerunners soon realized that conventional naval tactics were ineffective against the parasite's onslaught, they developed new weapons and tactics to combat the Flood. The Sentinels were deployed as a means of maintaining the Flood through surgical, localized tactics. The Forerunner fleet command even contemplated using naval battle groups to enact premature stellar collapse within compromised planetary systems, causing supernovae to engulf entire worlds. However, as these tactics proved only to slow, but never stop the expansion of the Flood, the Forerunner leadership realized that the only way to stop the Flood was to deprive it of any and all hosts, thus eliminating its potential to grow.

The Firing of the Halo Array
Even at this late hour, the Forerunners were reluctant to use the Halo Array, believing that they should continue to embrace the Mantle and to protect life rather than to destroy it. This led to great stretches of anguished debate and even civil war, but eventually it was decided that the Array was the only means of successfully stopping the Flood threat. The Gravemind managed to convince a Contender-class AI, 032 Mendicant Bias, to unite with the Flood. Mendicant Bias soon led his massive fleet in an attack on the "Maginot Line", the final barrier between what the Forerunners could protect and what they were forced to abandon to the Flood. At last, the Forerunners exhausted every alternative and activated the Halo array, killing themselves and all sentient life of sufficient biomass in the Milky Way, with the exception of those species safely placed on the Ark.

After the Array was fired and the Flood had been eliminated, the species the Forerunners had placed on Installation 00 were returned to their home planets. Whether this was done by remaining Forerunners (it is unclear if any survived) or through automated means is unknown. If some Forerunners remained, then it appears that they chose to leave the galaxy for unknown reasons. It is also possible that they could have left to occupy new galaxies or simply to escape the Halo Array when it fired.

Physiology
The Forerunners were a bipedal species slightly resembling humans, and they possessed hair on their heads and fur of some kind on their shoulder area. Their skin color ranged greatly, including gray, blue, pink, or a mixture thereof. The Forerunners may have possessed five-fingered hands, but this may have been Cortana's interpretation of the evidence available to her. Form-Zero Manipulars such as Bornstellar Makes Eternal Lasting resembled humans to some degree. They also had a genetic code that was remarkably similar to humans, though they were not known to be genetically related. All Forerunners wore personal body armor which featured many functions, including protection from harm and medical assistance. This armor also eliminated their need to sleep, and made their lifespans basically indefinite.

Forerunners were extremely long-lived; the Librarian, for example, lived on Earth for ten thousand years, and had most likely been alive for considerably longer.

Mutation
When a Manipular was ready to work within a particular rate, they would undergo an artificially-induced transformation into a more advanced form, which differed depending on the Manipular's chosen caste. Referred to as a "mutation", the transition typically occurred over a long period of time. A typical Forerunner would undergo several mutations over the course of a lifetime, though this was not always the case. Mutations altered Forerunners' abilities and physical shape to suit their class; Warrior-Servants, for example, underwent mutations that made them stronger and more robust. After their first mutation, Forerunners also gained the ability to access the Domain.

In emergency circumstances, an operation known as a "brevet mutation" could be performed on a Manipular. This was a mutation that occurred over a much briefer period of time, and was often painful. Rarely, a brevet mutation could fail and result in deformities. The Didact performed a brevet mutation on Bornstellar Makes Eternal Lasting to give him access to the Domain.

Culture
The Forerunner civilization was based around the Mantle, a belief that it was their role to protect all life in the galaxy. They monitored the evolution of other sentient species throughout the galaxy, intervening in ways that ensured their civilizations would follow paths of peace, free of conflict. The Forerunners themselves were a race almost entirely without conflict, and although political disputes were not uncommon, violence or war between Forerunners was almost unheard of. As such, the Warrior-Servants who conducted most of the Forerunners' military operations were considered the second lowest rate in their society. While they generally strove for peace, when provoked to a war, the Forerunner Warrior-Servants would carry out the war ruthlessly and thoroughly, as they believed defiance of their rule was equal to showing contempt to the Mantle itself. One example is the Human-Forerunner wars, where many humans were executed following their defeat, and all traces of human achievement was erased from the galaxy.

The Forerunners had a rigid social structure, where one's position would be determined mainly by their rate, a system of different social classes mainly based around a particular occupation. Cultural practices and customs varied by rate and position; generally, Forerunner culture was full of formality and ritual, particularly with the Builders. During special occasions, each rate of Forerunners wore unique ceremonial headgear except for one day of Grand Star Season, when all rates would wear similar headgear.

Despite their lack of need to sleep, Forerunners had certain moments where each member of a household would retreat for several hours of individual meditation. These moments were typically arranged according to the local day-night cycle, and were sacrosanct in traditional Builder families. During this time, the activities on an entire planet would slow down, including traffic and even the operations of ancillas.

Languages
Forerunners spoke a variety of languages. Some dialects were older than others, and accordingly were less widely used. Digon was an ancient language used by Prometheans, while Jagon was a slightly less old language used by Builders.

Societal classes
Forerunner society was divided into a number of different classes known as "rates", each rate seeming to specialize in a particular field of work. "Manipular" was a term used to refer to adolescent individuals.

Funerary rites
When a Forerunner died (usually by accident or, on rare occasions, during war) elaborate ceremonies would be enacted before their remains were disposed of in fusion fires associated with the activities of their rates — a melting torch or planet cutter, for example.

First, the Forerunner's last memories would be extracted from his armor, which preserved a few hours of the occupant's mental patterns. This reduced splinter of personality would be placed in a time-locked Durance, which has a half-life of more than a million years. The body would then be torched in a solemn ceremony attended only by close relations. A bit of plasma from the immolation was preserved by the appointed Master of the Mantle, who secured it along with the essence in the Durance. The Durance was then given to the closest members of the dead Forerunner’s family, who were charged with making sure that it would never be abused. Families and rates were very protective of such places, and tampering with a family Durance was considered sacrilege.

Slipspace travel
After making a slipspace jump, Forerunners of high position, including Councilors, would conduct a ceremony where they formally congratulated the ship's ancilla and would in turn receive a small golden disk containing the cost of particle reconciliation for the journey.

Forerunner technology
The Forerunner's technological achievements were without parallel in the known galaxy. They managed to create solidified surfaces out of light, use Slipspace to teleport between locations almost instantaneously, and create numerous forms of advanced machinery. The Halo Array and the Shield Worlds are, above all others, the most significant pieces of surviving Forerunner technology. Another of their greatest achievements is their ability to initiate pre-mature stellar collapses of stars and create planets in less than 10,000 years. The planet Onyx and its Dyson Sphere in particular demonstrated both their ability for engineering on a grand scale, and their near transcendent grasp of slipspace technology. Forerunner technology is remarkably resilient, being able to remain intact for over a hundred milleinia.

"Luminaries", which were originally designed to pinpoint Forerunner technology, were used to find "relics" by the Covenant. They are also capable of locating Reclaimers. A misunderstanding of a Luminary's readings led to the outbreak of the Human-Covenant War.

The Huragok, biomechanical "supercomputers" created by the Forerunners, remained behind after the activation of the Halo Array. Many were eventually incorporated into the Covenant.

The Forerunners had the technology to reproduce entire individuals from encoded DNA/RNA/silicon samples in data streams.

Spacecraft
Forerunner spacecraft used special crystals to travel through slipspace. In order to move through ordinary space, they utilized a reaction drive which harnessed virtual particles as a propulsive force.

The interiors of all Forerunner ships were not entirely composed of matter; for example, the structure of a planet-breaker was only half matter, with one third being fuel and reaction mass and the rest being comprised of hard light, allowing the captain to configure the ship's internal layout and decoration at will. At least some types of Forerunner craft can alter their geometry to better suit their current situation; for example, making the ship more aerodynamic in preparation for surface landing.

Certain Forerunner ships could be "grown" from a "design seed", being manufactured on-site from "blueprints" contained in a highly compact set of building materials.

Weaponry
Forerunner constructs and sentries use a broad variety of weapons, typically high-powered energy beams. These weapons proved to be very effective when battling the Flood, burning Flood forms to the point that they cannot be revived by infection forms. The Forerunners were able to merge beams together into one stream to amplify its power. The Forerunners installed and constructed these intricate beam weapons inside their paradigm Arrays, allowing them to build an army of machines to battle the Flood without sending any Forerunner to the front lines. The Forerunners evidently made active use of plasma weaponry as well; the Covenant's own weapons and technology are based solely on Forerunner artifacts. It could also be that these are forerunner light-based energy weapons, yet the Covenant have not yet been able to unlock their full power, much like the Dreadnought - and are only able to produce plasma due to lower energy output.

The Sentinels wield orange-colored directed energy beams, used primarily for fighting the Flood. Sentinel Majors, however, have a more powerful and accurate version of the beam, which sports superior energy output, at the cost of overheating issues. These more advanced energy beams are colored blue. All variants of these Sentinel Beams can be wielded by humans and certain Covenant races.

Meanwhile, Enforcers are equipped with multiple packs of small grenades, or mortar-like explosives launched over the top of their shield. The Enforcer also boasts a pair of pulse beams, which fire clusters of smaller red Needler-like projectiles or bolts of energy at an incredibly high rate of fire. These pulse beams are primarily used against infantry at close range. These mammoth constructs also seem capable of lifting even tanks, using some sort of magnetic or anti-gravity grapple, before crushing the target between their massive 'arms'. The Constructors' repair beam can also be considered a weapon, but with minimal damage output. Super Sentinels, Protector Sentinels, Strato-Sentinels, and large, tank-like automatons are used on other installations.

The Sentinels of Onyx had significantly more powerful weaponry. They were comprised of a sphere surrounded by three floating "booms" that generated powerful energy shields which would suddenly "pop" into place in order to deflect objects moving at high velocities. Their shields were not activated by slow-moving objects, however - SPARTAN-III Team Saber used this to their advantage to destroy one of the Sentinels with rocks. Their energy weapons functioned via a single, slow-charging, golden beam that could melt straight through the Semi-Powered Infiltration Armor used by the SPARTAN-IIIs. Linda-058 observed that one blast from these weapons was enough to drain the shields of her Mark VI MJOLNIR armor. The Onyx Sentinels also had the ability to combine for different purposes, such as exponentially increasing their combat capabilities, or for large-scale excavation. One formation of these combined Sentinels was able to easily destroy two Covenant destroyers. However, it should be noted that the second destroyer was caught off guard after a slipspace jump, and that the first one had its energy shields down in a gesture of peace, trying to initiate contact with the Forerunner constructs.

The Forerunners also constructed automated turrets that fire blue beams similar to those of sentinel majors. These turrets resemble stripped-down sentinels, and hover in mid-air, tracking enemy targets, but are otherwise immobile.

Monitors are capable of defending themselves with high-powered pulse weapons akin to those used by Sentinels, as well as with gravity manipulation technology.

In combat, the Forerunners themselves used advanced exoskeletons called Combat Skins and wielded powerful beam weapons.

Art and architecture


Forerunner architecture distinguishes itself from Covenant structures in that it incorporates heavy use of geometric angles, usually at either extremely sharp degrees, as the Forerunner buildings are usually triangular, or at forty-five degree angles, most notably seen on Installation 04. Most Forerunner architecture is constructed with a special type of silver-gray metal that resists deterioration, bullets, plasma bolts and fire, as made evident by Forerunner structures standing in pristine condition 100,000 - 150,500 years after they were built. However, their resistance to plasma fire is more limited; concentrated plasma discharge is capable of destroying some Forerunner architecture. Other structures and certain starships were built with a golden-bronze colored metal.

Many symbols and patterns on Forerunner structures employ complex geometric shapes that appear to operate in dimensions higher than human understanding can comprehend. The Forerunners also decorated the interiors of their structures with a complex pattern of engraved straight lines and applied decorative touches and designs to nearly everything that they built, from structures to weapons. Even Sentinel drones possess small holographic Forerunner script around their "eyes". Forerunners decorated the inside of their homes and constructed other objects using a technology called hard light. This decor was absent on military installations such as the Halo Array.

The Forerunners were highly skilled at creating natural-looking habitats, such as those of the Halo installations, which tend to be very elaborate and include realistic weather patterns and self-sustaining biomes. Forerunner structures were designed to compliment the natural landscape, as opposed to the human idea of replacing it.

Forerunner astroengineering
While the Forerunners' architectural and technological prowess is legendary among the Covenant, their masterpieces also extended to the fields of stellar engineering. The Shield World within Onyx existed permanently in slipstream space, where planets and stars cannot ordinarily exist, and Installation 00 was located far outside the galaxy. Shield Worlds of another type were utilized as technology caches by the Covenant. One such Shield World was discovered by the. This world had an outer crust like Onyx, but its inner Dyson sphere was accessed through a long narrow tunnel hidden under one of the oceans. This Dyson sphere, unlike the Onyx Dyson sphere, was not separated in slipspace but was actually constructed on what appeared to be hollowed out inside of the planet. This sphere seemed to have had an artificially created or miniaturized sun, as it was able to fit within the confines of the planet's diameter.

The Forerunners were capable of moving and manipulating entire stars for use in their megastructures; at least two Forerunner sites, the Shield World within Onyx and the Micro Dyson sphere that held the Apex, made use of suns where none should exist. The sun at the center of the Dyson sphere where the Apex was housed was abnormally small, in order to accommodate the planet-sized Dyson sphere. Whether these suns are artificially engineered or simply moved from another star system by the Forerunner is unknown: either would have been an enormous technological achievement. Installation 00 also made use of an artificial star that emitted plasma for illumination. It is known that the Forerunners at least experimented with manipulating young stars by 100,000 BCE, employing stellar-class Engineers known colloquially as "plasma jockeys". They had also harnessed dozens of stars for energy production by using sophisticated energy fields to direct the energy output of a star.

In addition to stellar manipulation, the Forerunners could considerably speed up a planet's formation, artificially collapsing an asteroid field into a molten mass, then cooling it down and forming it into a terrestrial planet in less than ten thousand years.

Forerunner glyphs and symbols


The Forerunner glyphs seem to be based on a series of circular, complex shapes. The glyphs have been inscribed almost everywhere Forerunners were once present, from different areas of Earth, to the Halos. They were also known to put these glyphs and symbols onto their weapons, machinery and clothing, something the Covenant also copied, evident with the Forerunner symbols placed on the hilt of the Energy Sword and on the Sangheili Combat Harness. One of the most well-known glyphs is the "reclaimer" symbol.

In addition to the well-known symbols and logograms, the Forerunners also utilized a more conventional writing system. The characters used in forerunner writing have been described as resembling a series of dots, bars and triangles.

Forerunner in Covenant religion
The Covenant venerate the Forerunners as gods and refer to them as the "Ancients" or "the Gods". The Covenant believed that the Forerunners disappeared from the galaxy after the Halo Array elevated the Forerunner to a state of trans-sentient godhood. As such, they have appropriated many Forerunner technologies and artifacts, and such searching led to the Covenant coming to Harvest in the first place, therefore beginning the Human-Covenant war. The most holy of these artifacts, the Sacred Rings or Halo Installations, were seen as the means by which the Forerunners ascended into divinity. The Covenant believed themselves to be the chosen inheritors of the Forerunners' legacy, and by locating and activating the Halo Array, the Covenant believed that they too could follow the Forerunners into godhood. This is referred to as the "Great Journey" by the Covenant races.

Trivia

 * The Forerunners show some similarities (their highly advanced technology and the fact that they mysteriously vanished) to the Jjaro, a race of aliens from a previous Bungie game, Marathon. The concept of a highly advanced extinct race leaving technological relics behind is not a new concept and is indeed a fairly common element of science fiction of all media, from books, to films.
 * The Forerunners were the main focus of the alternate reality game, Iris.
 * The Forerunner Saga, a trilogy of books based on the Forerunners' culture and their war with the Flood is in the process of being written by Greg Bear. The first of these books was released on January 4th, 2011, called Halo: Cryptum.
 * In Halo, the last campaign mission in Halo 3, there is a cutscene in which a rampant 343 Guilty Spark says to John-117; "You are the child of my makers. Inheritor of all they left behind. You are Forerunner." This, among other things, has led to many fans to conclude that Humanity and the Forerunner are one and the same. However, it has been clarified in later material that while humans and Forerunners may be genetically related, they are two separate species. The Forerunners merely intended humanity to be their successors, and likely did something to the species as a whole to allow Forerunner technology to recognize them. This would explain why the Covenant device for finding Forerunner artifacts always sees humans as moving artifacts.
 * The most likely cause of the Forerunner's interest in Humans in particular is that the two races had extremely similar base genetic codes. This would be of interest to a species such as the Forerunner because of the improbability of the situation: two home planets, two species, two distant points in the galaxy; all leading to virtually identical organisms. This similarity led the Forerunners to theorize that humanity was also shaped by the Precursors.