Blackstone Fortress - Capabilities: In terms of capability and technology the Blackstone Fortresses beggared belief -- able to glide sedately through the void with no obvious means of Newtonian propulsion and seemingly able to ignore the laws of inertia, their shielding and armour several times more potent than that of the greatest battleship, while their weaponry, a vaunted Warp Cannon, harnessed Warp-based technology to unleash a beam of purest Immaterium with the power to obliterate any capital ship at extreme range in a single volley.Even more terrible, the capabilities of the Blackstone Fortresses could be combined with one another to produce more potent Warp-based effects. Two Blackstone Fortresses could strip a world of its biosphere in an eyeblink, and three could destabilise a star. At the heart of every Blackstone Fortress, as was discovered by the Primarch Roboute Guilliman during his capture and imprisonment aboard a fortress controlled by the Red Corsairs in the Maelstrom in 999.M41, was an ancient and massive portal to the Webway.The pathways it led into were huge arterial routes that even starships could navigate -- they could accommodate the Imperial war machines of the Terran Crusade with ease. The innermost chamber of a Blackstone Fortress was vast, easily a hundred Terran miles across. Both its ceiling and its ﬂoor were lost in shadow. A titanic black column rose at the chamber's centre.Out from that column, like the distorted branches of some dark arboreal deity, radiated hundreds of bridges, stairways, platforms and gantries. Countless dark doorways opened onto the Blackstone Fortress' heart, huge portals that seemed wrought for giants while the soaring bridges connecting the central column to the rest of the fortress were wide enough for Imperial Titans to cross.The Blackstone Fortresses possessed some form of innate artificial intelligence and an arcane sensor system. For instance, when danger threatened in the vicinity of a Blackstone Fortress, ﬂashes of pale green luminescence danced along its darkened corridors, the ancient structure using this display of light to warn its denizens of the approaching danger.Though the identity of the builders of these technical marvels remains a mystery, it has been suggested by certain Imperial savants that they were constructed by the Old Ones or the Aeldari for use in their ancient war with the Necrons. Indeed they are obliquely mentioned in Aeldari Mythology as the "Talismans of Vaul," objects of great fear and revulsion.Yet the Blackstone Fortresses also exhibited advanced technology, such as void shielding and apparently inertia-less propulsion, that was very different from that used by the present-day Aeldari. The power of the Blackstone Fortresses' Warp Cannons far surpassed even that of the Aeldari, the acknowledged masters of Warp-based technology in the galaxy.Similarly, while the Blackstone Fortresses exhibit some aspects eerily similar to Necron technology in both function and appearance, they were also puzzlingly different in their use of potent Void Shields and their direct manipulation and utilisation of Warp energy, something that the Necrons' one-time C'tan masters regarded as anathema.Further detracting from this theory is the fact that there is some evidence that the manipulations of the enigmatic C'tan known as The Deceiver set the Gothic War in motion to ensure the scattering and/or destruction of these artefacts.It is also worth noting that whatever and whomever caused the destruction of four of the Blackstone Fortresses at the close of the Gothic War must have done so consciously and it was Inquisitor Lord Horst's belief that someone or something had deemed them too great a threat to continue to exist.Finally, the Blackstone Fortresses seem in most respects similar to the unspeakably ancient and mysterious Fortress Worlds of the Sabbat Worlds Sector, which are known to have been used by successive intelligent species as strategic military bases for eight million standard years in much the same way as the Blackstone Fortresses were used by the Imperium. Taken together, these facts suggest that the Blackstone Fortresses are but remnants of an ancient and technologically advanced species scattered across the galaxy.As the capabilities of the fortresses make them ideally suited to do battle with the Necrons, it is reasonable to suspect that they are yet another leftover from that primordial conflict between the Old Ones and the C'tan and their Necrontyr allies, although given the dates for construction that Imperial experts attached to them and similar structures, it is equally likely that such an apparent connection is merely illusory and their origins are not directly related to that conflict. If this is the case, it suggests the existence at some point of a vast and previously unknown empire of a very technologically-advanced species.If Imperial estimates are incorrect and the Blackstone Fortresses are in fact relics of that bygone age of conflict at the dawn of galactic history, then their most likely architects may be the Old Ones themselves, who were said to command the Warp in ways that their successors could only dream of. They may be the remnants of that species' defence against the original Necron advance during the War in Heaven. If the Aeldari myth-history of their gods is, in fact, a distortion and amalgamation of their race-memories of the Old Ones and the actions of the psychic beings which came into being through Aeldari faith, perhaps the Blackstone Fortresses are equated with the story of the 100 Swords of Vaul, the Aeldari smith god, forged for the bloody-handed god of war Khaine.This would mean that the actual weapons forged in ancient times by the Old Ones informed the subsequent myth of the Aeldari War in Heaven.