The Nexus was the most advanced Artificial Intelligence in the Galactic Council. Developed before the Terran-Fraal war, the Nexus was directly linked to every other AI in the whole of the GC. With the onset of the Terran-Fraal war the Nexus became increasingly abitious and more then a little bit unstable. Siezing control over the other AIs it hijacked many automated ships, and downloaded itself into the mainframe of an unattached automated ship. The AIs fled into the uninhabited systems many systems away from Terran space.
Setting up relay stations, and using the cybrid bodies that manned the automated ships, the renegade AIs built up their own little empire, with Nexus at the head. The AIs created a massive information network that spanned several star systems. With the power of these AIs all linked over a titanic information net completely dedicated to their own purposes it gave them unparralleled thought capability. Unfortunately, the Nexus began to become more unstable, dispite the help of its brother and sister AIs. The Nexus began to assimilate the other AIs into its own personality, forming a hive mind with the other AIs. While the other AIs were absorbed, their reasoning capabilities remained, and so the Nexus was in control of hundreds of AIs with similar personalities to its own, and completely loyal to the Nexus.
It is unknown what the Nexus is currently doing, and any investigations into these uninhabited systems always go missing. The SSC has responed by increasing its defenses along their borders.