Even though they make extremely rare appearances in the Halo series, the Forerunners are an incredibly important part of the story. As the creators of the Halo rings, the Forerunners are indirectly responsible for many events in the popular gaming franchise.
However, the narrative of the Halo games takes place millennia after the Forerunners became dead and gone. As such, their species remains shrouded in mystery. Luckily for you, we've compiled some of the more important facts about the Forerunners that every Halo fan should know. Read on if you want to know more about the makers of the Halo Array.
10 They Destroyed Their Own Homeworld
As evidenced by all the Halo rings, Shield Worlds, and that gigantic Ark we see in the games, the Forerunners knew how to fiddle with planetary-sized locations. Part of their growth as a civilization involved their acquired knowledge of galactic engineering. They learned to build planets. However, they weren't always masters of this craft. They lost their original homeworld, Ghibalb, when it was destroyed due to an accident during an experiment with planet building. They had to construct a new world for themselves, called Maethrillian.
9 Forerunners Wear Armor All The Time
Forerunners evolved to require armor about themselves at all times. It might have originally started as a cultural thing, but their armor eventually became necessary to their way of life. It gave them unique access to the Domain, denoted their class, and extended their life span. As players, we only ever saw a Forerunner without an armored helmet when we were introduced to the Didact and the Librarian. Most terminal cutscenes showed the Forerunners in full armor. However, only specialized Warrior Forerunners had armor conducive to fighting, called a combat skin.
8 Their Society Functioned On A Strict Class System
Forerunner society was separated into different classes. Instead of the word "classes," these segmented portions of their civilization were called rates. There were Lifeworkers, Warrior-Servants, and Builders to name a few. Before a young Forerunner joined a rate, they were part of an adolescent class called Manipular.
It was usual for a Manipular to go into the rate that their family was a part of. The two primary Forerunners we know, the Didact and the Librarian, belonged to the Warrior-Servant and Lifeworker rates respectively.
7 They Believed In The Mantle Of Responsibility
If the Forerunners were to be said to have any religion, it was a belief in the Mantle of Responsibility. In Halo 4, players can hear the Didact spout off a bunch of nonsense about this "Mantle." Essentially, the Mantle stated that as the most advanced and able of the sentient beings in the universe, the Forerunners had a responsibility to protect, nurture, and encourage other sentient species scattered across the cosmos. This Mantle was passed down to the Forerunners by their forebears, the Precursors. Though as we'll later explain, the Forerunners' time keeping the Mantle was meant to be temporary.
6 The Domain Was A Precursor Construction
In Halo 5: Guardians, Cortana is brought back to life after she touches the Domain. Though initially believed to be a Forerunner construction, the Domain actually comes from the Precursors. The exact nature of the Domain is unclear. All we know is that it is a "neurophysical" space that holds all information that the Precursors and Forerunners gathered during their lifetimes. Think of it as a nearly infinite, quantum search engine. It holds the records of basically everything, including the experiences of individuals. When Cortana accessed this thing, she was restored to "life."
5 Their Name Implies They Would Be Replaced
The Forerunners' name implies that their civilization is meant to precede something. It's a name that is meant to be succeeded, if you know what we mean. The Precursors, the species that created the Forerunners, intended humanity to be the civilization that would replace them. That's why, as we find out in later Halo games, humans are referred to as "Reclaimers." However, not all Forerunners were pleased at the notion that humanity, not themselves, were to be the true inheritors of the Precursors' legacy.
4 They Created The Flood
Eventually, the Forerunners rose up against their makers, the Precursors. What was left of the Precursors after they were destroyed turned into dust. And while it is not clear whether the Precursors made or became the Flood, we do know that after their transformation into the infectious parasites, they attacked the Forerunners with a vengeance.
There is even evidence that despite the Flood's ferocity when it first attacked ancient humans, it turned on the Forerunners with even more hatred. Because of their actions in wiping out the Precursors, the Forerunners spelled their own doom.
3 Humanity's Devolution Is The Forerunners' Fault
When humanity first ran into the Flood on their planets, they aggressively expanded onto other worlds. Forerunners mistook this expansion for an expression of humanity's violent tendencies, not realizing they were fleeing the Flood. Thus began the Human-Forerunner War. Thanks to their superior technology, the Forerunners won. As a punishment for their aggression, the Forerunners devolved humans. Forerunners basically set humanity down a few rungs on the evolutionary ladder. Humanity needed to start from scratch after that.
2 Two Didacts Existed
This might sound confusing, but there were two Didacts alive at one point. The Ur-Didact was the original Didact, and he is the one that Master Chief encounters in Halo 4. He firmly believed that the Mantle belonged to Forerunners, and he hated humanity. The other Didact, known as the IsoDidact or the Bornstellar Didact, was once a young Forerunner Manipular. This Manipular took on the consciousness of the original Didact, becoming a kind of copy. The IsoDidact was created because Forerunners initially thought that the original was dead, and they needed a skilled Warrior-Servant to lead them against the Flood.
1 Their Ancilla, Mendicant Bias, Betrayed Them
Forerunners created AIs just as humanity eventually did, too. Their AIs were called ancillas. The Forerunner's primary ancilla was called Mendicant Bias. This intelligent construction was in charge of the Forerunners' defense against the Flood. Unfortunately, a Flood Gravemind was able to corrupt Mendicant Bias, turning him against his creators. It is partially due to Bias' betrayal that the Forerunners lost and had to activate the Halo Array as a last-ditch effort to halt the Flood.