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 Forerunners.

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. 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 had taken up a role as custodians of the galaxy, and believed that this "Mantle" had been passed down to them by the Precursors, an even more powerful race that preceded the Forerunner civilization. "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. Before their disappearance from the galaxy, the Forerunners would name humanity their successors, identifying them with the title "Reclaimer".

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 and their war with the Flood.

Origins


The Forerunners were created by the Precursors, and millions of years before rising to power, they overthrew and exterminated their creators, leaving only one. Records of this war was eventually lost to time, and Forerunners of 100,000 BCE thought that the Precursors simply "disappeared".

The Forerunners originated on the planet Ghibalb in the Orion complex. The world served as the hub of the Forerunners' fledgling interstellar civilization, comprised of twelve systems within the nebular complex, 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 and nearly caused their extinction.

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 and the seat of the Ecumene Council, was constructed around 125,000 BCE. The Forerunners reached their peak before activating the Halo Array around 100,000 BCE, in the closing days of their war with the Flood.

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, splintered among its collective species 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 war with humanity, 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 Conservation Measure, 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 on the planet Seaward 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.

Firing of the Halo Array


Even at this late hour, the Forerunners were reluctant to use the 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 resembling humans in overall shape, though they were larger in stature. Before their first mutation, they were tall and slender, and possessed patches of fine, purple-pink or white fur on the top of their heads, along their nape and shoulder area, as well as the backs of their hands. Their facial features were similar to those of humanity, and they were capable of making analogous expressions, but this changed as they mutated to their higher forms, which characteristically had stiffer facial muscles and a more limited ability to convey emotions. The Forerunners also had a genetic code that was remarkably similar to humans, though they were not known to be genetically related.

Their skin color ranged greatly, including gray, black, blue, pink, or a mixture thereof. The number of fingers Forerunners possessed seems to have varied according to their rate and form; Lifeworkers, for example, were known to have seven fingers, while Bornstellar's later form, based on a mixed pattern, had six fingers.

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; the Librarian, for example, was over eleven thousand years old by 100,000 BCE.

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.

Society and 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 often looked down upon by the higher rates, as their actions were perceived to be contradictory to their role of preserving life. While they generally strove for peace, when provoked to a war, the 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, part of a complex 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. Forerunners placed a great deal of value on family lineage and tradition, and one's rate and social standing were largely hereditary.

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.

Forerunners did not eat meat, as the Mantle forbade "the eating of the flesh of unfortunates".

Some Forerunners rejected their advanced technology, including personal armor, and adopted a more austere and primitive lifestyle in seclusion from the rest of Forerunner society. One such community existed on Seaward, which would incidentally become the first planet in the Forerunner ecumene to be overrun by the Flood.

Societal classes
Forerunner society was divided into a number of different classes known as "rates", each rate specializing in a particular field of work. The Builders, who designed the Forerunners' various megastructures, were the highest rate and wielded the most political power. The second rate were the Miners, who obtained construction materials for the Builders' projects. Below the Miners were the Lifeworkers, who were responsible for medicine and biological research. The Warrior-Servants, the primary fighting force of the ecumene, were the fourth and second lowest rate. The lowest rate were the Engineers, who were tasked with constructing and operating Forerunner structures and machinery, as well as planetary and stellar engineering.

The rates, in turn, were divided into smaller units, guilds, Maniples and clans. Adolescent individuals, known as "Manipulars", were not considered to be part of a rate until their mutation into first-form. 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.

Family and marriage
Forerunner customs involving marriage were said to be complex; they married for a variety of reasons, though it was said that the lower rates married more often for love, while there were often more complex reasons such as familial relations involved in the courtship of higher rates such as Builders. Intermarriage between rates was not unheard of; for example, the Didact, a Warrior-Servant, married the Librarian, a Lifeworker. At certain points in their lives, females would enter a "millennial interim", a period when they would not bear children.

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.

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.

Space travel
Traditionally, Forerunner space travel involved several rituals. When a Builder family was returning from an interstellar journey, the entire family would stand at the bridge deck and observe the ship's approach. The senior family member would issue commands in ancient Jagon. These actions were entirely ceremonial, as nearly all Forerunner ships were controlled by an ancilla.

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.

During prolonged space journeys, Forerunners would often play "diverting games" to pass the time.

Technology
The Forerunners' technological achievements were without parallel in the known galaxy. They managed to create solidified surfaces out of light by using technology known as hard light, use slipspace to teleport between locations almost instantaneously, and create numerous forms of advanced machinery. 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 Halo Array and the Shield Worlds are, above all others, the most significant pieces of surviving Forerunner technology. 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 millennia.

The Forerunners had mastered the use of various energy fields, including buffer fields which they used to manipulate gravity, constraint fields used to restrain individuals, confinement fields used to block the movement of entire ships, and the containment and collection fields they used to harness entire stars for energy production.

Forerunners utilized various camouflaging technologies, including dazzlers, which generated visual and auditory delusions, or bafflers, which created geometric distortions that could effectively hide a large area not only from plain sight, but also a starship's sensors.

Forerunner technology could also produce certain objects remarkably quickly without extensive production facilities. For example, personal armor could be manufactured by small engineering units onboard a starship, and entire ships could be "grown" from a "design seed", being manufactured on-site from pre-programmed "blueprints" and construction materials obtained from local resources.

The Forerunners had mastery of instantaneous interstellar communication and information transfer, as demonstrated by their vast ancestral information network known as the Domain, which was accessible to any Forerunner at will, or their ability to track slipspace jumps across the galaxy. It is not known what Forerunners use for day-to-day communications, but it is mentioned that Forerunners never use electromagnetic radiation (light, radio, microwaves, etc.) to communicate, most likely because it would be far too slow, and prone to interference.

"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.

Biotechnology
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.

The Forerunners were also capable of extracting an individual's brain patterns and memories; typically, part of a dead Forerunner's final memories were typically recovered and stored in a container known as a Durance. In a mutation, part of the mentor's consciousness would be transfered to the individual being mutated through their genetic imprint.

Recovered memories or specific commands could also be coded into a generations-long genetic imprint known as a geas. Memories or messages stored within a geas could be programmed to trigger under specific circumstances.

Spacecraft
Forerunner spacecraft used special crystals embedded in their slipspace drives to travel through slipspace. In order to move through ordinary space, they utilized a reaction drive which harnessed virtual particles as a propulsive force. In addition, the Forerunners created a network of slipspace portals for high-traffic slipspace transit across the galaxy. Aboard starships, limited inertial dampening was achieved through the use of buffer fields, but during extreme acceleration, the occupants' armors had to be locked to the deck.

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.

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 made active use of plasma weaponry as well; the Covenant's own weapons and technology are based solely on Forerunner artifacts.

The standard Aggressor 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 missile launchers and 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. Watcher Sentinels, Protector Sentinels, Retriever Sentinels, and unidentified 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 trapezoidal, 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.

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.

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 glyphs, 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.

Forerunners 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.

Production notes

 * According to Evil Otto, Bungie's intentions for the connection between humanity and Forerunner was that they were one and the same; this was hinted repeatedly throughout the Halo Trilogy and further explored in Staten's novel, Halo: Contact Harvest. However, the Terminals of Halo 3, as well as the release of the first two books of the Forerunner trilogy released by 343 Industries have revised this, establishing that the two species were related but distinct and that the actual connection goes far further back than the events in the books, when both species had been created by the Precursors.
 * In the cancelled Halo MMO, Forerunners were depicted as humans with tanish skin and white hair. This design is similar to the Atlantians from Disney's Atlantis the Lost Empire. The design of the Forerunners greatly resembling humans may be based off of Bungie's original intention on Humans and Forerunners being the same.

Miscellaneous

 * 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, titled Halo: Cryptum, while the second novel, Halo: Primordium, was released on January 3, 2012.

List of appearances

 * Halo: Combat Evolved
 * Halo: Combat Evolved Anniversary (Terminals only)
 * Halo 2
 * Halo 3
 * Halo Wars
 * Halo 3: ODST
 * Halo: Reach
 * Halo 4
 * Halo: The Fall of Reach
 * Halo: The Flood
 * Halo: First Strike
 * Halo: Ghosts of Onyx
 * Halo: Contact Harvest
 * Halo: The Cole Protocol
 * Halo: Evolutions - Essential Tales of the Halo Universe
 * Dirt
 * The Mona Lisa
 * The Return
 * Soma the Painter


 * The Forerunner Saga
 * Halo: Cryptum
 * Halo: Primordium
 * Halo Legends
 * Origins
 * Halo: Uprising
 * Halo: Helljumper
 * Halo: Blood Line
 * Halo: Glasslands