On the surface, and holding up under fairly heavy probing, the Atlan Ascendancy was a typical imperial state. A pseudo-independent stellar nation, in the heart of the Jugurtha Subsector, pious and fervently loyal to the Emperor.
The Hive-World of Atla itself was rather young for its kind, the last bits of land being buried in civilization only a few hundred years prior. The planet, second in its system, had always been hot, but now it was unbearable. So the people delved into the cool darks of the planet's crust, living out their lives in one of countless hive-worlds spread throughout the galaxy.
While it suffered from the degree of criminality and lawlessness that plagued all hive-worlds, it was for the most part fairly peaceful. I must again stress, peaceful in terms of hive worlds.
Vandra and Takat, the Third and Fifth planets respectively, provided much of the Hiveworld's food. Vandra was a committed Agri-World, while Takat had only recently been reclaimed from Orks. Settlement and exploitation was slow, as Feral raids continued to attack settlers, but Atla had more than enough humans to make up for these minor losses.
So the planet-city of Atla continued its daily life, transforming the raw resources in other parts of the nation into finished products, more ships to plow their way through the empty space of the Eastern Fringe, or more weapons to fight agaisnt the various forces of heresy and Xenos prevalent in the sector.
However, deep within the tunnels of Atla, and on several other surrounding planets, an infestation had been spreading, stealthily and silently, closing its tentacular grip on the nation.
Deep underground, a dully-glowing, yet strangely beautiful set of eyes opened.
Patience will always pay off, my brothers and sisters. Our time draws near...