GAIA is the main A.I. overseeing Project Zero Dawn. A personification of Mother Earth, GAIA is tasked with the re-terraforming of Earth back to its original state.
The product of Project Zero Dawn, GAIA is the main Artificial Intelligence charged with overseeing the re-terraforming and reseeding of life on Earth after its destruction at the hands of the Faro Swarm. GAIA was located at the massive underground facility known as Gaia Prime, which housed its computer core and other subordinate functions needed to ensure proper management of the re-terraforming process.
She stayed largely in contact with Elisabet Sobeck, to the point that they became good friends, with GAIA declaring that she knew Elisabet all too well. However, Ted Faro feared that should the AI become corrupted, there should be a fail-safe, to which Elisabet did not approve, but GAIA accepted as an emergency course of action.
Sometime after GAIA was activated, the Alphas evacuated to GAIA PRIME, but she made them aware of a malfunction in the door that could make the swarm aware of them. With GAIA's help, Elisabet sacrificed herself for their safety. Soon after, Ted Faro contacted the Gaia Prime team in an attempt to explain himself. Using his security clearance, Ted Faro purged the APOLLO education and historical archive system, wiping out thousands of years of history and consigning future generations of humanity to ignorance and primitive lifestyles. Faro then went even further, and commanded the facility to vent its oxygen supplies, killing all of Gaia Prime's personnel.
Despite this unspeakable move, GAIA maintained her role in not only deactivating the Faro Swarm, but also bringing life back to the planet. She made the majority of her machines to regenerate life and detoxify the planet, and ordered cradle facilities to begin repopulating the planet, but understood that without the help of APOLLO, the population was not able to communicate with her, nor vice-versa, and saw that the humans had become primitive compared to the late 21st century.
In the 31st Century, GAIA received a transmission from an unknown source. This transmission had the immediate effect of causing all subordinate functions to become self-aware and erratic. One of the sub-functions, HADES, attempted to seize control of the terraforming system to destroy humanity. Unwilling to let this happen, GAIA activated a fail-safe, in which the reactor of the Gaia Prime facility was commanded to self-destruct in the hopes of destroying HADES. A second fail-safe was activated by ordering a gestation chamber in a Cradle Facility to create a clone of Elisabet Sobeck. This clone, upon reaching physical maturity, would be able to use her DNA to enter all Project Zero Dawn facilities in hopes of rebuilding GAIA.
However, HADES reacted in an unusual way by unleashing a virus to destroy the code holding it in place, causing HADES to escape to an unknown location. This had the adverse affect of corrupting data, including the Alpha Registry, the DNA security-system at the Cradle Facility which had the unfortunate result of effectively disabling the clone's ability to enter the Cradle to view GAIA's message.
- GAIA is based on the Greek primordial deity Gaia who is the personification of Earth and the ancestral mother of all life. In Greek mythology, Gaia is the ancestor of all Greek deities. Similarly, she is the grandmother or great-grandmother of all named sub-routines contained within her AI.
- Sylens states that it may in fact be possible to rebuild GAIA by using the Cauldrons' foundries to make the necessary parts; however, this could take years, and in any case the effort would be for naught until HADES is stopped and prevented from interfering.
- The death of GAIA had many unexpected consequences:
- Without a central governing system, the machines soon began to become deranged and attack humans without warning.
- Without an extended backup to stop any subordinates from becoming self-aware, HADES attempted to wipe out any trace of the work GAIA had achieved.