Koylegan system

The Koylegan system was located in the Acheron Nebula, located out the outer edge of the North Arm of the Crucible Galaxy. The star system is particularly rare in that it was formed when two binary white dwarfs collided with one another to restart nuclear fusion. As such, Koylegan is considered an undead star of sorts.

Fittingly, the God machine Necros made this star system his capital where he once ruled over a society of undead - deceased organic life forms brought back to life through complex EM waves and nanobots. Necros' most loyal followers were known as the Boneyard Necromancers.

Planets

The Necropolis

The Necropolis is located deep within an ancient nebula formed from the violent deaths of the stars of the Acheron Nebula. It appears within a half-formed planet with an exposed core filled with dark, looming architecture representative of a graveyard. Bones of enormous creatures can be seen frequently incorporated into the architecture.

Necros' AI core once resided here though for millions of years, it has remained in a standby mode. It is thought that the Necropolis was meant to be completely underground, but its bizarre appearance was more than likely the result of an Anathema attack after it was determined that Necros was being energy inefficient. Given that the destruction of the Necropolis seems incomplete, it is more than likely Necros put up a fight.