Stronghold-class Commerce Vessels belong to the xenos species known as the Demiurg, a mercantile race allied to the Tau Empire. Stronghold-class vessels are typical of the Demiurg's vessels and are extremely well-powered, large, and technologically advanced starships. They serve as mobile factories or ore-processing vessels and often act as bases for the Demiurg which are moved between star systems and asteroid belts as they seek out richer sources of raw materials. These starships also often serve as bases for the Demiurg's fleet of intersystem asteroid mining pods, cargo-hauling flyers and prospector probes (it is believed that many of these are automated). Typically, lone Demiurg Strongholds have been encountered in the flare or mercurial zones of uninhabited star systems, hanging motionless and prow-on to the star with a cloud of small craft busily hustling to and fro to exploit the local stellar and planetary resources.
In most cases these ships withdraw their craft and disengage if challenged but in some instances have inexplicably turned on their attackers with a surprising ferocity. It is worthy of note that every known encounter between Demiurg and Ork vessels has resulted in combat and that Imperial renegade elements have often hired Demiurg vessels to fight as mercenaries in interplanetary and intersystem struggles. As warships, Demiurg vessels are slow but well-defended, boasting considerable firepower at close ranges due to its potent Lances and possession of a prow-based laser cutting beam intended to be used to slice apart asteroids for mining but easily repurposed to serve as a potent weapon. Stronghold-class vessels also maintain the capacity for launching mining craft reconfigured as Attack Craft and torpedoes.
Some Rogue Traders have reported that Stronghold-class starships serve as the homes for up to three Demiurg clans or Brotherhoods and are essentially the mobile fortresses of this nomadic species. The sociopolitical nature of Demiurg Brotherhoods or what the relationship between those who share a single vessel might be are not yet understood by Imperial scholars. Stronghold-class starships are often seen in uninhabited star systems with fleets of smaller ships moving resources to and from the vessel and a planet or asteroid, with the prow facing the star.
A notable trait of the Stronghold-class is its employment of an array of powerful electromagnetic fields around its prow to serve as a Bussard Scoop that will absorb interstellar hydrogen. This hydrogen is accelerated to the rear of the vessel to speeds near that of the speed of light to provide motive force as a ram-jet but the complex radiation shielding it requires evidently produces numerous other defensive benefits for the starship. This process is not understood by the Adeptus Mechanicus and the Tech-priests are eager to get their hands on an intact Demiurg vessel to analyze it.
- Online Tau Fleet List