The primary setting of the Angelfyre series is a cluster of star systems within the Cygnus Constellation.
After the human and Fel alliance of the standard earth year of 2199, the Joint Cygnus Mission led to a settlement beyond the Cygnus Rift on the planet of Starstep-93c, later to become known as Stelerean Prime. In the years to follow, dozens of other civilizations had joined the Cygnus System Cooperative, and in the standard year of 2289 the United Systems Charter led to the formation of the Stelerean Constellation (a politically defined sub-constellation of the Cygnus Constellation).
The Stelerean Constellation is a collection of systems within a spatial volume of approximately 8 million cubic light years. Not all systems within the constellation are members of UniSys, some instead opting for complete independence from the charter. Nonetheless, their sovereignty is fully respected, and they are free to trade with member systems and move about unhindered provided they respect the world and sentience rights protection provisions of the UniSys Charter.
Within the Cygnus cluster of stars, the Stelerean Constellation marked the majority of known sentient races within the Milky Way Galaxy. A few outliers existed, including Earth over 2 200 light years away, although the small number of expeditions to the far reaches of the galaxy as of 2421 had thus far failed to reveal any additional civilizations to those already known by this time. Later theories speculating on the development of life bearing worlds hinted at the unique properties of this portion of the local Orion-Cygnus Arm, particularly a region between the Orion Nebulae and Cygnus-X that offered superior stellar stability in its main sequence stars.