Architect

The Precursors were an advanced, ancient space-faring race who arrived on Planet 4546B 1000 years prior to the events of Subnautica in search of a solution to cure the infamous Kharaa virus. Precursors are almost 100% mystery, however a Data Bank entry claims that ninety-six years old is seen as young for a Precursor. It was also mentioned that Precursor young were grown from seeds, implying plantoid or fungoid biology. Precursors are/were (presumably) much larger creatures than humans due to the sheer size of the rooms in their bases, and most objects within. It is possible that the Precursors were biomechanical entities, however, due to the fact that a (possibly) ordinary bacterium could affect them may disprove this theory.

The Precursors were clearly an extremely advanced race; Much more than humans. They had the capability to travel across galaxies, implying incredibly advanced spacecraft and propulsion technologies. They had the technology to create robotic drones that could survive in severely heated areas, teleporters and a weapon capable of destroying huge ships (such as the Aurora). They also had the capability to produce biomechanical lifeforms, presumably through advanced gene engineering. Precursor technology requires "keys" or "artifacts" to open certain forcefield gateways via an Artifact Terminal.

Kharaa Plague
The Precursor civilization was destroyed by the Kharaa, a bacterium that spread quickly to many Precursor worlds and causes sickness and death. Billions of Precursors died, although seemed to have the technology to store their consciousness digitally before death.

Planet 4546B
Planet 4546B was designated as a Disease Research Facility planet. The Kharaa was tested on local species hoping one would show a resistance to the bacteria.

Extreme safeguards were put in place to prevent the spread of the Kharaa offworld if it ever leaked into the local ecosystem. The Quarantine Enforcement Platform (QEP) is a colossal Precursor superweapon designed to destroy any unauthorized spacecraft from entering or leaving Planet 4546B's atmosphere. Precursors also created a synthetic race, known as "Warpers" or Self-Warping "Quarantine Enforcer Units". These self-teleporting bio-mechanical creatures were advanced enough to track and kill all fauna in advanced stages of Kharaa infection.

Other structures on 4546B include the Thermal Power Generator (PTPG), A base situated in the Active Lava Zone, which draws power from the nearby lava to power Precursor structures. And the Primary Containment Facility (PCF), an aquarium that contains the Sea Emperor, a creature which is immune to the Kharaa.