Horizon Zero Dawn came out in 2017; a lifetime (five years) ago. It was a super lore-heavy game with a lot of important characters, factions, and worldbuilding that can be a bit difficult to recall so many years later. The bad news? You need to remember a lot of what happened in the first game to really get Forbidden West. The good news? I'm here to help you out with this handy guide.
Ok, from the beginning.... who is Aloy again?
Aloy is the hero of the Horizon saga, the flame-haired outcast from the East. Aloy was an outcast from the local Nora tribe since the day she was born: she was found at the entrance to the Nora tribe's sacred place called The Sacred Mountain. The Matriarchs, the spiritual Nora leaders, were split between seeing this red-headed babe as a blessing from the goddess or a curse. Considering the Sacred Mountain is off limits to everyone but the Matriarchs, it looked pretty likely that the baby was not born to a human mother- a big no-no in the matriarchal Nora society. To be on the safe side, baby Aloy was cast out to be raised in the wilds by Rost, another exile.
Aloy grew up shunned from the Nora tribe, and spent most of her childhood preparing for The Proving: a rite of passage where upon completion, she would be an accepted member of the Nora clan. Aloy, our master parkour-erer, manages to win the Proving and becomes an official Nora -- yay! Unfortunately, the Proving is attacked by cultists called the Eclipse who are hell-bent on hunting down Aloy. Thus begins Aloy's journey.
How did the world end?
In the 2060s, tech industry icon and CEO of Faro Automated Solutions, Theodore Faro, began investing in self-replicating military robots that could hack into enemy systems and absorb organic mass to replenish fuel. Wanting to ensure that such machines could not be captured and taken apart, Faro demanded that all machines be designed without backdoor systems. Due to a "glitch," these machines targeted their owners and began to replicate uncontrollably. The rogue AI and spread of killer robots would eventually be known as the "Faro Plague."
Following the surge of machines, Faro brought in scientist and former colleague Elizabeth Sobek to develop a solution. She predicted that the machines would escape containment and spread at a high rate-- resulting in the inevitable end of all life on the surface of Earth. To make matters worse, the machines' need for biofuel would extend to humans, giving them a massive source of sustenance. As humanity faced the inevitable, the super-wealthy escaped the planet on the interstellar ship Odyssey. At the same time, the remaining governments of Earth banded together to form Project Zero Dawn -- which was created by Sobeck.
What is Project Zero Dawn?
With no hope to stop the machines, Project Zero Dawn was humanity's last attempt to give life on Earth a second chance. Designed by Elizabeth Sobeck, PZD was a large network of underground bunkers, cloning facilities, and machine creation hubs to re-terraform the planet. The network would be organized by an advanced AI named GAIA, which had 9 subroutines that would assist the remnants of humanity to rebuild civilization and hack into the systems of all rogue machines - both of which would take over a century to accomplish.
While the remaining military and civilian forces fought machines in an unwinnable fight, scientists and engineers worked on Project Zero Dawn to ensure its success. Sometime after machines had overtaken Earth, a distressed Faro - who had access to Project Zero Dawn - would delete the Apollo database, which was a compendium of all human knowledge. His reasoning was to hide his involvement in the Faro Plague and give humanity a fresh start. He also killed the entire human leadership Project Zero Dawn to hide his guilt.
Though several setbacks occurred over the centuries after the machines became docile, human and animal life would eventually return to the surface -- giving the world a second chance.
Who is GAIA?
GAIA is the world's most powerful AI and governing AI behind Project Zero Dawn. Created by Elizabeth Sobeck, GAIA is in charge of all the subordinate functions that have jobs to do in restarting earth after it was destroyed by the Faro Plague. Like GAIA, the functions were all named after Greek deities.
AETHER: In charge of detoxifying Earth's atmosphere.
APOLLO: an archive of human history and culture, which was destroyed by Ted Faro to eradicate evidence of his guilt in ending the world.
ARTEMIS: reintroduction of Earth's animals, from genetic stocks saved in special facilities.
DEMETER: reintroduction of Earth's plant species from genetic stocks, much like ARTEMIS.
ELEUTHIA: reintroduction of the human race by cloning humans and raising them in fully automated "Cradle facilities".
HADES: reversal of unsuccessful terraforming attempts i.e: make the world lifeless again if GAIA messed up.
HEPHAESTUS: manufacturing of all those machines- originally known as Zero Dawn terraforming machines
MINERVA: carries and sends out Faro Plague deactivation codes, and constructs towers to broadcast these codes.
POSEIDON: detoxifying Earth's water..
Who is HADES?
Hades was one of the nine "functions" part of Project Zero Dawn. Its job was to make the planet lifeless again if Gaia's terraforming process was a failure in order to restart the process. At some point in the 1,000 years following the world ending, Hades was given a signal making it into an AI. It then went rogue and was able to leave the facility with the other subordinate functions.
Sylens discovered Hades and helped it learn about the current world in exchange for knowledge about the old world. Thanks to Sylens restoring a network of Focuses, Hades was able to reactivate the robots that destroyed mankind. The two also concocted a plan to create a cult around Hades in order to have a human army.
At the end of Horizon: Zero Dawn, Aloy was able to stop Hades before it could complete it's goal of using the Spire in Meridian to activate all the deactivated robots across the world. Some time after its defeat, Hades was able to escape its core and was captured by Sylens.
Who is Sylens?
Sylens is a self-described researcher who has an attraction to technology. He investigated the GAIA Prime ruins where he discovered a damaged Focus. After repairing it, Sylens picked up a signal that eventually led him to Hades.
After escaping from Hades and the Eclipse cult, he overheard an order from the AI to kill a girl, which he eventually found to be Aloy. He helped Aloy throughout her journey by giving her information about where to proceed as well as saving her life. Sylens parts ways with Aloy before her battle with Hades, but he gives her a spear to deactivate Hades.
Sylens is a really mysterious figure who always seems to have an ulterior motive. Have we seen the last of Sylens? Time will tell.
What is Aloy's connection to Elizabeth Sobeck?
Aloy is a clone of Elizabeth Sobek, the scientist and engineer who created Project Zero Dawn. Aloy was created by one of GAIA's subordinate functions, ELEUTHIA, who was in charge of birthing the next generation of humans.
When GAIA destroyed itself in an effort to stop HADES, Elizabeth's genetic material was released to create Aloy in the hopes that one day she would be able to reboot GAIA.
What is Far Zenith?
For every person that wants to save the world, there's a bunch of rich people who would rather just escape to space. Far Zenith was one such organization: a shadowy group of some of the world's wealthiest people who wanted humans to colonize outer space. When news of the Faro Plague became public knowledge, Far Zenith sped up plans to get the hell out of dodge. Unfortunately, building a spaceship very quickly doesn't guarantee a super safe ship. The official story? Far Zenith's ship, the Odyssey, exploded when trying to leave the solar system, killing everyone on board.