The Flood. One of the most loathed enemies in all of video gaming history, the scourge of the Halo Galaxy, and the ancient enemy of humankind. Anyone who has played the Halo games knows the Flood well, but despite their importance to the Halo story, little has been divulged in the games themselves that explain the origin of the space parasite.
However, Halo’s vast and expansive lore has offered an explanation as to how the Flood came about, and that is what we will be exploring today. Strap in, because this post not only delves into some deep, deep Halo lore, but this story is long. Really long. Millions of years long, actually, as our story begins in roughly ten million years ago, give or take a few hundred thousand years.
Before delving into the tale, we must first establish the main players. Before the Forerunners even existed in the Halo universe, there was another race that dominated the Galaxy – the Precursors, a near-omnipotent race of shapeshifters who utilised their extremely advanced, magic-like technology to hold the Galaxy in balance. They created the Mantle of Responsibility, the philosophy of a single race having a duty of care over the rest of the Galaxy, and they held the Mantle for eons.
However, the Precursors eventually decided that the time was right to pass on the Mantle of Responsibility to a new race. As they had created every race in the Milky Way, the Precursors had to choose which of their creations would inherit their most treasured cultural and political achievement. Initially, it fell to the Forerunners to inherit the Mantle, but at the last minute the Precursors decided that it would be Humanity, not the Forerunners, who achieved this noble goal.
Needless to say, the Forerunners were less than happy with this decision. Either due to feelings of resentment or as revenge for the denial of their ‘birthright’, the Forerunners rose up and attacked their creators. Despite the fact that the Precursors were almost all-powerful, they had no combat experience whatsoever. They were shocked that one of their own creations would defy them to such a degree. In time, the Precursors were all but destroyed.
As such, the Forerunners claimed the Mantle of Responsibility, and the remaining Precursors were forced to flee to the far edges of the Galaxy. Desperate to survive, the last of the Precursors employed several methods to prolong their existence. Some went into stasis, some left the Galaxy altogether, but most decided to use their shapeshifting ability to take the form of a fine powder, which was held in containers and left to drift in space until such a time when the Precursors could return to prominence.
Meanwhile, the Forerunners assumed the role of Galactic custodians and the Humans were none the wiser to this entire conflict. For some time, things continued on in relative peace, with the Forerunners keeping order and the Galaxy essentially ticking over as the Precursors intended. That is until the previously mentioned fine powder was discovered by ancient Humanity.
Located drifting cargo ships that would occasionally crash-land on planets near the edge of their space, Humankind discovered the powder in dozens of transparent cylinders and, after some testing, found that it was harmless and useless, but nonetheless took some for study. They began to test the powder on small domesticated animals called Pheru, basically the ancient Human equivalent of a modern Canine, and found that over time the powder promoted docile behaviour in the creatures.
The populatiry of these Pheru spread throughout the Galaxy. Other races, such as the San’Shyuum, began to take Pheru as pets. For hundreds of years, nothing happened. Then, just as the Pheru had become as engraciated within Human and San’Shyuum society as possible, the first signs of what would soon be called ‘The Flood’ began to show.
The Flood Rises
The behaviour and physiology of the Pheru exposed to the powder began to change at an alarming rate. First, soft loose fur began to grow on the backs of some Pheru, which other Pheru often consumed. This was odd, as Pheru were known to be herbivores. Eventually the fur began to be replaced by small, fleshy growths – these were also consumed by other Pheru, and led to birth defects and more radical changes in their behaviour. The infected Pheru became aggressive, and to make matters worse the early signs of the infection began to show on Humans as well.
Before long, the infected Humans began to consume the flesh of their fellows. Throughout Human space, panic ensued, and the same was true for the San’Shyuum. Before long those that had become infected were almost unrecognisable, they began force-feeding their infected growths to other humans, and the Flood spread like wildfire. Before long they were primed to wage war against the Ancient Human Empire.
And wage war they did. The Flood ravaged Human space, forcing them to flee across the Galaxy. This leads into the events described in the Halo: Combat Evolved Anniversary Terminals, to sum up briefly, the Humans aggressively fled into Forerunner space with the Flood hot on their tail, the Humans began sterilising planets that showed signs of Flood infection, and in response the Forerunners, completely ignorant of the Flood threat, cast judgement over Humanity and regressed them to a primitive state.
Due to their haste in condemning Humanity, the Forerunners were caught off-guard by the Flood ten thousand years later. Nobody is quite sure why the Flood waited so long to attack – the Forerunners believed that Humanity had found a temporary cure, but by now it was far too late to ask them about it. Others suspected that the Flood waited deliberately in order to maximise the impact of their sudden attack, similarly to how long the Pheru took to mutate being put down to a conscious decision by the Flood so as to not raise suspicion.
Whatever the reasons, the Flood attacked after a centuries-long wait. Caught off guard, the Forerunners lost dozens of colonies and billions of Forerunners were infected within just a few years. A horrendous campaign ensued in which the once mighty Forerunner empire was whittled away as the Flood continued their relentless advance. In response, the Forerunners became increasingly desperate.
The Forerunners created an advanced Ancilla known as Mendicant Bias, an AI designed to destroy the central intelligence of the Flood – the Gravemind. Unfortunately, Mendicant Bias was infected by the Logic Plague and defected to the Flood. The Didact’s plan to use a Composer on Humanity to create a new race of Promethean soldiers was undone by his wife, the Librarian, who at this point was dedicated to a programme of galactic conservation. Machinations within the Forerunner political elite meant that, after exhausting every other strategic option, the Halo Array was developed and deployed to wipe out all sentient life in the Galaxy.
The tragic history of the creation and development of the Flood is one of Halo’s darkest tales. Whilst it is easy to point the blame at the Forerunners for their own fate, they did eventually make the ultimate sacrifice in the hope that the Flood would never return. Unfortunately, due to their desire to ensure the Flood could be cured, the Forerunners also used the Halo Rings as research facilities, storing Flood specimens there. This ensured that the Halo Array, a weapon designed to be the ultimate counter to the Flood, was actually the Flood’s ultimate salvation – and given that a Halo Ring is confirmed to be present in the upcoming Halo: Infinite, we can be assured that the Flood will make at least a minor appearance after years of absence.