The Line

When the Forerunners realized that they lacked the infantry and military to capably defend individual worlds and systems, they began developing several failsafe plans.

The first plan they devised and implemented was what is referred to as the Line. This wasn’t a literal line which divided the galaxy, but a spherical barrier, the Maginot Sphere (as it was referred to), which housed various Forerunner populations and worlds.

The term ‘Maginot’ is not a Forerunner term but rather the name of a Prime Minister in France who built a protective border against Germany before the beginning of World War II. It’s used here is as a descriptor from 343 Guilty Spark (who translates the Forerunner language for the Master Chief), since no other human word was deemed appropriate.

This sphere was a protective measure when attempts to attack and destroy the parasite had proven unsuccessful. From here the Forerunners did their best to remain in the shadows of the galaxy, keeping the barrier a secret from the parasite while still waging what war they could beyond the Line.

The substance which formed the barrier is unknown, however some evidence points to it being a blockade of ships, while other evidence indicates that it may well have been an energy-based barrier. Either way, the sphere effectively stayed the encroachment of the Flood.

Exactly what part of the Forerunner population lived within the sphere isn’t clearly defined, but some text suggests that their leadership and individuals of privilege were at least the first to be allowed passage. We are also led to believe that the Ark (Installation 00) may have been created within the shield during this time or it is possible, that the sphere itself was specifically built around the Ark.

In Forerunner text, the location of the sphere and the Ark are synonymous – which could place the sphere at the edge of the galaxy since part of it lies within the Halo Array’s reach and part of it is outside the rim, where the Ark resides. Whether or not the Ark may have moved during this ordeal is not known, although probable given its location in Halo 3.

The existence of the Ark and the sphere point toward another series of plans – last resorts – which were being considered during the darkest hours of the great war. One of these plans would ensure the end of the Forerunners’ way of life.

Plans Within Plans

Toward the end of a three hundred year battle with the parasite and despite some minor successes, little overall progress had been made. At some point, there was a decision of such significance that it shook the very core of the Forerunner belief system.

This decision led to the creation of the Halo Array.

With the Mantle starting to be overshadowed by the terrible reality that was the Flood, military campaigns had already begun glassing and razing entire planets. Worlds which had been infected were destroyed collectively rather than the introduction of ground forces which had proved completely ineffective against the Flood. There was even the suggestion of collapsing nearby stars which would eliminate or at least stop the progression of the Flood through certain systems.

When they recognized the futility in diminishing the parasite’s numbers, the Forerunners developed the Halo Array and the Conservation Measure. It is uncertain which came first or if they were developed simultaneously with each other, but their overall purposes became interconnected at some point.

The Array began with the building of the Ark. This artificial cradle world, acted as both a remote control station for the Array network (existing outside the effect of the Array itself) and as a foundry for the production of the individual network installations, seven ring-like habitats commonly referred to as Halo. These networked installations served two specific functions: firstly, as a containment laboratory for the study of the Flood and secondly, as a network of weapons which could produce heavy pulses of energy designed specifically to kill intelligent life.

The installations, when fired in unison, would effectively destroy every sentient (infected or uninfected) within three radii of the galaxy’s center. Having placed the installations at specific locations throughout the galaxy, once the Array was activated, it would halt all known sentient life. Although the seven installations still contained individual specimens of the infection, they were enclosed behind heavily-augmented quaratine walls and monitored by AI constructs who served as the caretakers of the installations.

No one truly knows why the Forerunners did not destroy the individual specimens along with the launch of the Array, as they would be considered a serious risk if the parasite ever escaped. Some have speculated that they did not have time to deal with the specimens before the Array’s activation or that they simply have trusted the AI caretakers of the installations with the safekeeping of the specimens. It is more likely, however, that the Forerunners continued to study the Flood through automated measures, hoping to gain knowledge for future sentients, on a way to eliminate the Flood if it ever returned.

The Conservation Measure appears to be the other side of the Array coin.

Building a series of expeditionary parties, a group of Forerunners embarked from the Ark on missions which placed them deep into the center of the galaxy, far outside the protection of the Line and right in the middle of the sprawling Flood infection. They used gargantuan Keyships, massive dreadnoughts capable of carrying thousands upon thousands of passengers, and filed off toward the center of the conflict with one goal: to index, catalog and recover as many uninfected sentients as they could, sending them back to the Ark for safekeeping when the Array purged the galaxy.

When the Array’s activation ended, they would be returned back to their own planets.

Their method of transit back home, however, would be different. On several worlds they visited, the Forerunners built machines which could generate portals. These gateways would form upon activation and would be buried deep underground. The Keyships were the only vessels capable of accessing and opening the machines, which would, in turn, create a portal into subspace allowing direct access to and from the Ark.

One such gateway was placed on the human homeworld, the planet Earth. For this world, there was an even greater design, a plan within a plan which could not come to past until considerably later. Humanity would be an important key in the Forerunners’ inheritance and in the Array’s reclamation process.

With the Array being a last resort, the Forerunners developed one final attempt to destroy the Flood. Under the belief that the Gravemind’s own destruction could stop the Flood, the Forerunners plotted their most strategic assault yet. They would attack the Mind directly.

Having learned that the Gravemind becomes vulnerable and recoils when reaching a certain size (allowing the infection to hedge around it for protection), the Forerunners planned to strike it remotely and with all of their available power. In order to do this, they would have to instigate the attack from an extremely close proximity and for this reason they created an artificial intelligence construct unparalleled to all which came before it – it was essentially sentient.

Although this mission began with hopeful optimism, the Forerunners would soon learn that it would be their most grand folly.

The Contender

This contender-class AI construct was designed with the sole purpose of drawing out the parasite’s central intellect, the Gravemind and then begin gathering information from it. When instructed by the Forerunners, the AI would then unrelentingly attack the Mind until the beast withdrew from their galaxy or perished.

This construct was called Mendicant Bias or MB.05-032 and it was charged with the protection of the Forerunner race at any cost. The depth of the error with this charge would only be realized by the Forerunners in their final hour.

Upon the contender being sent out with a heavy arsenal of 1,000 core ships, it eventually made contact with the Gravemind. For approximately 43 years, Mendicant and the Mind spoke candidly with each other. The construct continually sent out transmissions to its Forerunner masters within the sphere, outlining the Mind’s arguments for its existence and data about the creature itself.

For those four decades, nothing was done by the Forerunners in response to this data – something which surprised Mendicant and eventually created a seed of doubt within its logic. This seed was all it took and it wasn’t long before the Gravemind had fully exploited the Forerunner construct’s weakness – its own self-awareness.

Making the eloquent argument that the Forerunners were impeding the natural order of things – the next stage in biological evolution – the Mind eventually convinced Mendicant that its makers had sent it as a catalyst for their own, subconscious willingness to accept the Flood. With Mendicant holding the keys to access the Maginot Sphere, the Forerunners were now in peril.

The exact reason the Mendicant’s makers never ordered it to attack the Gravemind is unknown. Some have speculated that the Forerunners were, in fact, exactly as the Gravemind stated – willing on a subconscious level to succumb to the parasite. Others have stated that transmissions to and/or from the Forerunners were being obstructed by the Mind at some point – which seems likely considering the location Mendicant had to travel to meet the parasite’s center. Whatever the case, without any command to attack the Gravemind, Mendicant was left pondering whether or not the parasite was right about its role in the galaxy and about the Forerunner’s intentions in sending it.

When the construct finally turned on its makers, it fell to rampancy – an AI’s form of insanity. Filled with rage (a predictable stage in rampancy), it led the Gravemind and almost five million Flood-infested ships toward the Line to assault the Maginot Sphere and eventually, the Ark.

When it arrived, however, the Forerunners had already prepared for it.

[Proceed to Part III]