The term “Halo” is one of those words whose familiarity and meaning was usurped by the success of a cultural work that shares a name with said word. Indeed, the Halo series seems to be associated with the term rather than its religious namesake.
Despite its image being tied to its science fiction aesthetics and military-centric plotlines, the eponymous Halos are indeed conceptually similar to regular halos that non-fans would be familiar with, especially due to the Covenant's worship of them. Although their functions are completely different from biblical halos in the long run, the Halo Arrays inspired the franchise’s name for a reason. They are a big player in both Halo lore and the actual games’ storylines.
Conception and Construction
The Halo rings are collectively known as the Halo Array. Although their capacity to exterminate a galaxy’s worth of creatures was initially an important plot twist in Halo: Combat Evolved, the Halo rings were in reality never more than a genocidal network of megastructures. Indeed, the Array’s creators, the Forerunners, explicitly intended for the Halo rings to exterminate all sentient life in the Milky Way galaxy. That being said, despite their destructive design, it is no coincidence that the Halo rings’ role in the original Halo game ends up being used as a last resort against the Flood.
The Flood was the reason why the Halo rings were built in the first place. The Forerunners’ Master Builder Faber built the first Halos after encountering the Flood in the Milky way for the first time. Alongside destroying the Flood if needed, the Halo rings were designed to have their own wildlife and weather, enriching the universe of Xbox's signature series' in the process. They were also meant to contain and study the Flood to the Forerunners’ benefit. Extremists insisted that the Halo rings should be built to protect the galaxy against the Flood, arguing that such a powerful set of weapons is the only way to stop an equally problematic threat. Although the process faced issues, such as design flaws and structural corruption on the Builders’ part, the Halo rings were eventually completed.
To round up the Array’s design, the Forerunners created an “Ark”, used to centralize the manufacturing of the Halo rings. The Ark was meant to function as a safe haven, a facility to make replacement Halos, and a space to activate all rings in the Array at once. There are a grand total of 18 Halo rings that have been created during the Forerunners’ reign. The first Array made up the original 12 rings, that were 30,000 kilometers wide each. They were created by the “Greater Ark”. The second Array had 6 rings that were 10,000 kilometers wide. Unlike their earlier counterparts, they were created by a different Ark, the “Lesser Ark”. Out of these original rings, only 7 would last and be included in the final version of the Halo Array.
Halo Rings and the Halo Universe
The first Halo ring to be tested was Installation 07. It was launched during the Forerunner-Flood war on the planets Charum Hakkor and Faun Hakkor, with the latter being the first victim of the rings’ potential for annihilation. Installation 07 was not only unique because of its connection to the earliest Array tests. It is also the oldest Halo ring and generally considered to be the most mysterious. It was part of the original Array and integrated into the newer one, making it the only Halo ring to have both diameters at some point.
Eventually, the Halo rings were discovered by both humanity and the Covenant. The latter faction, a multispecies alliance, was founded for the Halo universe’s equivalent to religious beliefs. They believed that the Array was the source of a “Divine Wind” that allowed the Forerunners to transcend physical spaces and become gods. To the Covenant, activating the Array would integrate them into the realm of godhood. Considering humanity’s goal to prevent the Halo rings’ activation in the storyline, these misguided beliefs are arguably a major cause for the Human-Covenant war.
Halo Infinite's campaign is now available for PC, Xbox One, and Xbox Series X/S.