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The Forerunners of the Halo series used to be quite the mystery, but as the series went on, and the lore got filled in with books and backstory inside and out of the games, these shadowy and strange aliens slowly emerged as a species of almost infinite power and ego.

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The Forerunner lore in the Halo series is absolutely fascinating and there is a huge library of interesting details and backstory to get lost in for hours on end. It can seem a little overwhelming at first glance, but once you scratch the surface, their impact on the wider Halo story becomes much more significant. So to condense their history into a somewhat manageable level, here’s everything you need to know about The Forerunners.

Who Are The Forerunners?

Halo: Forerunner Tech Discovered By The Covenant In Halo Waypoint Backstory

The Forerunners are an ancient race of hyper-advanced aliens whose vast Empire spanned entire galaxies. They were technologically advanced to such a degree as to seem almost godlike, and with substantially extended lifespans they would rule most of the galaxy for several millennia, leaving their influence and achievements on multiple worlds. Something that would lead to the rise of a certain group of religious zealots (the Covenant) in the far future.

They saw themselves as the Caretakers of the universe, and they’re the architects behind the Halo Ring system. Plus after its firing during the Flood Wars, they were responsible for seeding life back into the galaxy, though they themselves didn’t survive.

Origins Of The Forerunners

Halo: Precursor Art Shown In Halo Waypoints Cutscene

Unbeknownst to some, they are not the original beings in the universe as they themselves were created. The Forerunners are just one of many early lifeforms created by the Precursors, a staggeringly ancient race of Lovecraftian creatures whose sole purpose was the spreading of life throughout the universe. The Forerunners lived in peace with the Precursors for a time before rising up and overthrowing their creators in a bloody conflict that spanned galaxies and lasted eons.

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Believing themselves to be the perfect creation and worthy of the title of Mantle Of Responsibility over all life in the galaxy, the Forerunners were suitably shocked when they were passed over by their creators in favor of the early proto-humans and almost driven to extinction in the following purge by the Precursors who had deemed The Forerunners as being "problematic".

After a grueling conflict, The Forerunners emerged triumphantly, and with their domination of all life in the galaxy seemingly secured, they took the reigns of seeding life throughout the galaxy. So they're far from the pure and divine beings most races believe them to be.

The Golden Age Of The Forerunners

Halo: Example Of A Forerunner Ark Instillation

With the galaxy at their fingertips, the Forerunners experienced a reign of prosperity and advancement that the galaxy hasn't seen the like of since. They constructed vast mega architecture such as the Halo arrays and giant planet-spanning installations whose structures stood for millennia until the galaxy's current inhabitants stumbled across them in the far future after the Forerunners were gone. Their advanced technology gave them near-infinite life spans and their superior energy weapons rendered any battle into a one-sided slaughter.

This almost omniscient race seemed invincible, and they were...for a time.

The Downfall Of The Forerunners

Halo: Examples Of Forerunner Military Soldiers In Advanced Armor

Empires, no matter how big or small, eventually crumble to dust. Whether from invasion by a stronger force or rabid infighting, eventually, it all burns down. The Forerunner's fall from superiority was equal parts brutal and ironic. After wiping out early Humans (be de-evolving them) because they felt threatened by how fast they were expanding throughout the Universe,The Forerunners enjoyed relative peace for around nine millennia. It wasn't completely without worry though, as it was discovered that the reason humans were spreading so fast was to escape a horrific mutative parasite known as The Flood.

Though it was pushed to the far edges of the Galaxy, eventually the parasite returned, appearing at first as a mysterious disease that twisted its host into horrific shambling monstrosities whose only goal was to spread the pathogen further. It was not long after the pathogen took hold that the Flood bioforms got more complex and a full-scale Flood invasion started.

Thus began the Forerunner-Flood Wars, the last great battle the galaxy would see for a very long time.

The Forerunner-Flood War

Halo: Forerunners Observing Flood Parasite In Halo Anime

As brutal as this war was, what makes this conflict deliciously ironic is that The Flood are the Precursors, returned to the Galaxy once again after hiding from the Forerunners' purges as particles of dust. Unfortunately, this process drove the Precursors completely insane, twisting them and filling them with deep rage and the need to spread death throughout the galaxy. This was only possible after their dusty remains were inhaled as the unfortunate host would then undergo severe and horrific disease and mutation, becoming a shambling corpse, that would swell the ranks of The Flood.

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At first, the Forerunners were able to slow the Flood for a time, but their superior numbers and their ability to fill their army from the rotting dead and survive on as airborne particles should their Hives be razed to the ground made them incredibly difficult to put down for good. With multiple different mutations leading the vast hordes as well as the ability to use Forerunner technology such as Starships, the Flood managed to drive this one grand ancient advanced Empire to its knees until the ultimate sacrifice ended the entire conflict temporarily for millions of years.

The Firing Of The Halo Rings

Halo: Halo Ring Firing As Seen In The Halo Anime

An end to the war was achieved by performing the ultimate sacrifice, the firing of the Halo Ring weapon system. These Doomsday weapons sent out lethal blasts of energy at key points in the galaxy which wiped out all organic life, the sole food source of The Flood. With nothing to fuel themselves or their undead war machine they were either wiped out by the initial galaxy-spanning blast or starved out in an empty universe.

After a time, Forerunner tech that had secured samples of all the races in the Galaxy before the rings fired, storing them onboard Ring Arks, reseeded life to those planets that were within range of the rings. With the Universe starting over from scratch, the only trace of this once invincible empire remains in empty architecture, lost artifacts, and the minuscule number of Forerunner stragglers that managed to hide on shield worlds.

The Forerunner Caste System

Halo: The Forerunner Caste System And The Differences In The Species

An interesting thing about The Forerunners is that there's no singular type, they employ a strict caste system where individuals evolve themselves upon maturity through augmentation to fill a need within Forerunner society with each caste holding a significant position of power and political strength within the species hierarchy.

For example, at the top are the Builders who construct the vast mega architecture, then there’s the Miners, the Lifeworkers who seed and research new life, underneath them are the Warrior castes and military leaders, then the Engineers, and finally the Juridicals. Their physiology drastically changes to suit their role, so warriors are larger and stronger, whilst engineers are smaller and lithe and may have extra fingers on their hands or additional arms. It’s a sensible system that shores up any weakness within Forerunner society as everyone pulls their weight.

Forerunner Society

Halo: Forerunner Judicial Meeting In Halo Waypoint Logs

Contrary to their advancements in science, The Forerunners also had their own system of beliefs and are surprisingly traditional and family orientated. Their civilization was based around the Mantle Of Responsibility, a doctrine that stated it was their sole responsibility to protect all life in the entire universe.

On the surface, it seems like a peaceful belief structure, but in reality, it was their way of directing and controlling the evolution of species in ways they deemed fit. It either ensuring they didn't fall into periods of conflict or advanced to a point where they could potentially threaten the dominance of the Forerunners.

Everything the Forerunners did followed their teachings in The Mantle that they rigidly stuck to, which whilst efficient, did cause the race to stagnate somewhat as its strict structure didn’t really allow for a lot of wiggle room and anything too different was stamped out. Still, they rarely had conflicts and although political disagreements were not uncommon, all-out war was rare and extremely short-lived.

Notable Forerunners

Halo: Forerunner In Advanced Armour

Despite being mostly wiped out after their war with The Flood, a few Forerunners did survive, the most notable of which was The Didact who took the role of the primary antagonist in Halo 4. Aside from the aforementioned genocidal maniac, here are a few Forerunners who managed to escape the lethal blasts of the Halo rings and the slimy undead clutches of The Flood:

The Didact

The main military leader of The Forerunners, the Didact held a pathological disdain for Humanity. Seeing them as usurpers and unfit for the Mantle.

Halo: The Didact Without His Helmet in Halo 4

The IsoDidact

A Forerunner imprinted with a copy of the Didact's personality after he was thought dead during the conflict with the Precursors. Over time the original Didact's personality became dominant.

Halo: The Iso-Didact As He Appears In The Background Lore Of Halo

The Librarian

The Wife of the Didact, the Librarian's task was to catalog and conserve all forms of life in the galaxy to preserve them in the event of a catastrophe.

Halo: The Librarian Forerunner As She Appears In Halo 4

Faber Of Will And Might

Considered to be the Master Builder of The Forerunners, he was as talented as he was corrupt with every move made to solidify his political power and strength within his species.

Halo: Faber Of Will And Might Forerunner As He Appears In Halo Waypoint

Keeper Of Tools

Hidden away on planet Bastion, The Keeper Of Tools was a Builder that hid his consciousness away during the ring firing. Emerging thousands of years later during the events of Halo 5 where he tried to bring an end to Cortana's reign of terror after she took control of Forerunner Guardians during her Rampancy.

Halo: Forerunner Keeper Of Tools In Advanced Armor

Forerunner Technology

Halo: Halo 4 Promethean Knight Forerunner Enemy Ready To Attack

What made the Forerunners such a formidable force was their technology, as without that and the ability to physically augment themselves, they were relatively physically weak, instead they relied on specialized bodysuits that enhanced their strength and mental capabilities whilst also serving as a form of life support. Their weaponry also focused on plasma-based and hard-light technology which could cut through armor and burn away Flood infections with ease.

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Their advancements are nothing to be sniffed at as they provided near godlike capabilities, such as being able to create and seed life on any world they saw fit as well as build planet-spanning mega structures purely because they wanted to show off (no really, it's in the books). With such godlike powers at their disposal, it's little wonder future races such as The Covenant would hold them in such a deified regard.

Remnants of their advanced tech can still be found today in the modern Halo universe, either in the form of the Halo Rings, the Sentinels and the Monitors that protect and maintain these facilities, or the various artifacts that were found buried in forgotten Forerunner installations.

Forerunner Creations

Halo: Multiple Forerunner Halo Rings Floating Around An Ark

The Halo Ring Weapon System is perhaps the most iconic of the Forerunner creations. Supporting entire ecosystems, these seven titanic constructions are part living world and doomsday devices as they can release a deadly energy pulse that eradicates all organic life within the rings range, usually the entire galaxy in which it sat.

There were also the ARKs which served as shipyards for the manufacturing of these gigantic galaxy-ending weapons as well as shield worlds for many Forerunners looking to escape the firing of the Ring Weapons. The Forerunners were also able to create colossal artificial planets, such as Onyx, and also build or move stars at will. With such godlike technology at their disposal, if ever they were to return in any substantial form the universe would be in trouble.

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