Let us initially ignore any possibility of what the mod I'm currently working on will entail in terms of ships, weapons, factions, combat and campaign gameplay, and have a quick look instead at an idea I had for introducing it from a blank start, completely out of context.
Spoiler
The Silent Armada
Three cycles ago, they arrived. A Hegemony outer system patrol was the first to pick them up on long-range scanners. A silent armada of unknown, unregistered spacecraft pushing their way through Hyperspace. The numbers where vast, the sensor signatures otherworldly, the power readings never before seen... Yet not a single vessel showed any lifesigns. As a single autonomous unit, they ponderously edged their way into Sector space, making no moves to attack. Scouts were sent to investigate, and confirmed previous suspicions – the vessels were uncrewed, running on the barest of autopilot essentials, and possibly had been for dozens of cycles. Maybe hundreds.
But the strangest bit? The ships carried no data. Other than the most basic of computer programs, not a single ship had any form of flight data stored on their drives, leaving the sector dumbfounded as to their purpose and origin. While clearly intended for human use, these ships were built from technology either far in advance of our own, or ancient to the point of being forgotten to the grips of time. They were built for war, that was certain. But a war against who? Or what? The sector couldn't know.
Where had they come from? Were they sent many cycles ago by the old Domain, to travel through hyperspace until they reached the sector? If so, why would they carry no recordings or information? Perhaps they were merely leftover war vessels dismissed as junk, or the remnants of an ancient civilization making a desperate attempt to help their technology survive. Maybe the sector was not their final destination, but a waypoint in their endless, autonomous travels across the infinite star-speckled blackness of the universe.
Either way, the Hegemony has easily gained control of the plethora of warships. They have been relinquished of their autopilots and moved to Hegemony space where they may be examined by the best scientists, engineers and archaeologists the sector has. If they are lucky, some facts may be revealed, but for now, these weapons of war are an asset that cannot be wasted. So, they are being put to good use in the best way possible: Active military service.
Tell me what you think! ;)