The One Mind was a species of organic superconductors that dominated the Milky Way galaxy until their sudden disappearance. They created a system of Stargates which they used to navigate the galaxy.
The One Mind were organic, carbon-based superconductors. Nothing further about their physical structure is known.
The One Mind rose to galactic prominence fifty million years ago. During this time, they constructed a network of Stargates connecting the majority of the galaxy together. After twenty million years of dominating the galaxy, they abruptly disappeared, possibly transcending physical form. Following this, the Children of the Night took over the Milky Way. The One Mind's Stargates would remain in use well after their disappearance, and were later commandeered by the Xul to facilitate their spread across the galaxy.
The only known artifacts of One Mind technology are Stargates. Stargates are large wormhole generators, consisting of two small black holes rapidly rotating through a ring-shaped structure. While Stargates are usually around twenty kilometers across, they mass more than most planets. One Stargate can connect to any other Stargate.