After clearing out the NPC Fleets that had accumulated over the long stretch of time, one by one, Dimension Fortresses began to emerge in deep space, like lighthouses providing spacetime-coordinate navigation for friendly fleets across vast regions.
First, stable deep-space travel routes were established between the nearer Galactic Arms. Planetary fleets equipped with Dimensional Shuttle Engines, protected by the military's deep-space patrol fleets, began long-distance trade between the Galactic Arms, exchanging populations, supplies, and other resources to accelerate their development.
The effects of this trade on development between the Galactic Arms were difficult to discern at first, but the Empire's leaders were delighted to see that the establishment of deep-space trade routes had begun fostering interaction and integration between the various Galactic Arms, which had previously been relatively isolated because of the distances between them.
Quietly, the Governors' Mansions of the various Galactic Arms, once each a little kingdom of its own, began to feel the Empire's influence again. The barriers between civilizations created by distance gradually dissolved under this subtle, pervasive influence.
In the Gods' field of vision, certain branches of fate that had existed only in obscure corners of the River of Fate gradually blurred and vanished, giving rise to entirely new currents of destiny.
During the Planetary Era, before the Industrial Revolution, a nation's territory spanned only hundreds of thousands, or perhaps over a million, square kilometers. Larger territories merely led to fragmentation and decline, as was true of both Rome and the Tang dynasty. The advent of steam trains and telegraphs broke this limitation, and nations spanning hundreds of thousands or even millions of kilometers emerged.
In the Space Age, the limits that transportation placed on the area a civilization could govern remained just as clear. Without FTL routes, even whether a fledgling Interstellar Civilization could