Titus of Discord records the first Flumph incursion into Imperial Space some 300 years prior. The Empire enacted its ‘first contact’ protocols by sending elements of the 117th Frontier Fleet to wipe them out. While the fleet action was ultimately successful, the first incursion was soon followed by a second, larger group. Again, the Flumphs were wiped out, and again shortly thereafter a third incursion occurred, larger yet than the first two.
Deciding enough was enough, the Empire assembled an expedition, sending it into Unknown Space, to the alien’s presumed origination point. Their aim was to find the alien’s homeworld and ‘deal with it,’ permanently. Of course, as everyone knows, the expedition was never heard from again. Nor was the relief flotilla sent a decade later to discover the initial expedition’s fate.
By this time someone in the Empire finally noticed that the strange aliens almost always inhabited gas giants. If it weren’t for the valuable aetheric crystals growing deep within the gas giant’s core, the Empire wouldn’t pay any mind to such useless and desolate planets.
So, a kind of unspoken quid pro quo was reached. While Flumphs are still officially classified as a hostile invasive species, all military operations against them were halted. At the same time, private merchants were encouraged to approach the aliens to trade for the crystals, a far more efficient arrangement than the hazardous mining operations previously mounted by the Empire. Technically, trading with aliens is a crime punishable by slow disintegration, but the Empire looks the other way where Flumphs are concerned, so long as the Empire gets its cut of the crystal trade.
For their part, the Flumphs go about their alien business as if the Empire doesn’t even exist, interacting only with the crystal-traders that come calling. While they aggressively defend themselves against attackers (Imperial battle losses during the Flumph Incursions are still a closely guarded state secret), they otherwise ignore the Empire. They don’t even seem to bear any grudge for the many millions of Flumphs wiped out during the Incursions.
And so the Flumphs have achieved what no other advanced alien species has achieved before: a status of (near) equality with that of the Empire. It is estimated that Flumphs now inhabit hundreds, possibly thousands, of gas giants within the borders of Imperial Space, a veritable ’empire’ within the Empire. They are sometimes referred to as the ‘Great Flumph Empire,’ though you wouldn’t want to say something like that within earshot of an Imperial agent.