The Investigator and James Holden discovered a device within Ring Station that granted them access to records detailing the alien civilization's disappearance. It appears that the civilization had at one point stretched across the Milky Way Galaxy, and possibly beyond, and existed as a sort of hive mind or collective consciousness. At some point, an unknown agent began to "kill" portions of this hive mind, severing its connection to its component star systems.The civilization used the Ring Station to destroy the "infected" star systems by sending beams of energy through the Rings, causing the stars to explode and vaporize that system's Ring and planets. This proved ineffectual, however, and eventually the civilization enacted a quarantine by deactivating the remaining Rings. Whether through this action or those of the unknown aggressor, the alien civilization was subsequently rendered extinct. Events on Ilus following the arrival of the Rocinante revealed further information about the nature of the alien civilization and its collapse. It appears Ilus was once used to generate energy for other parts of the alien civilization, with a variety of structures having been embedded in the planet for this purpose. In one such structure, Holden and the Investigator discovered an object which appeared to have been left behind by the unknown agency responsible for the alien civilization's collapse.
Although very little is known about the alien civilization or its disappearance, the artifacts it left behind indicate a level of technological sophistication far beyond the greatest achievements of human science and engineering. Some of their most notable creations include the protomolecule, the Ring, the Slow Zone, Ring Station and the structures permeating Ilus, as well as the planet itself, to some degree.
Based on the nature of the protomolecule and the presence of animal-like biomechanical devices on Ilus and Ring Station, Dr. Elvi Okoye concluded that the alien civilization had great respect for the power of self-replicators, such as DNA, and based much of their technology around such molecules.
Many devices left by the alien civilization exhibit abilities that seem to manipulate fundamental physical properties. For example, the protomolecule-infected Eros Station was able to "dodge" the incoming Nauvoo without any apparent thrust or acceleration, and Ring Station was able to generate a field within the Slow Zone that prevented objects from exceeding a certain velocity. Additionally, the defense system on Ilus demonstrated the ability to nullify nuclear fusion within an unknown radius of the planet, preventing the ships in orbit from leaving.