Fortress Worlds (Segmentum Pacificus)
|This article is about the Artificial Constructs; for the Imperial Planet Classification, see Fortress World.|
The original creators of the Fortress Worlds are unknown, though they predate human activity in the Segmentum Pacificus by thousands, or even millions, of years. One of the several unknown xenos species that occupied them ended its period of occupation around M4. Similar structures have been found elsewhere in Imperial space, but offer little clue as to the original creators' identity.
The size of the Fortress Worlds made them ideal for military usage, for any civilization with sufficient resources to garrison and equip them. It is not known if this was the original purpose for which they were built, although at least one of the xenos species that occupied them, the Kinebrach, and certainly the Imperium and later the forces of Chaos, used them thus.
After the Sabbat Worlds cluster was overrun by the Archenemy in the 700s.M41, the Fortress Worlds became one of the most formidable obstacles to the Imperial reconquest of the sector. Morlond, in particular, was the "thorn" in Warmaster Macaroth's side, a nearly unassailable base for the Chaos fleets opposing the Crusade forces, and equipped with long-range weapons that could devastate the worlds already reclaimed.