4. Harpax

The Sentinel

Sole gas giant of Morologus Novem, Harpax stood as the system's custodian: it smothered asteroids, comets, and other bolides in the embrace of its colossal gravity before they could wreak havoc on the neighbouring worlds. However, and as the Mechanicum's first explorers had learned at their peril, its gravitational grip also tormented the many moons orbiting it.

Many were those of the Great Crusade who perished while studying the planet. Yet an even greater number had persisted, for the abnormally high density of its core—and the gravitational waves it provoked—was accompanied by an equally impossible presence of blackstone, in pharaonic quantities. This Noctilith, whose properties remained as promising as they were poorly understood, had sown confusion and covetousness alike through the ages. When Eti Gabatine’s fleet Cognos Kathartis foundered there, it reacted at first with incredulity, so improbable did it seem that this isolated system could withstand its proximity to the Great Rift. Later, some Magi postulated that the blackstone in Harpax's core may have guarded Morologus Novem from the horrors of the Immaterium, making the giant once more the unwavering protector of forgotten worlds.

In order to pursue its research, the Mechanicum had had no other choice but to establish its installations on the planet's third moon, soberly named Harpax III. The conditions on its surface were admittedly abominable, but the other satellites were too deeply bound to the planet's gravitational and magnetic fields for anyone to survive there for more than a few instants.

Tertia Harpaxis

Tectonic tides constantly twisted the crust of Harpax III, and unpredictable variations in gravity made any movement perilous. Moreover, a tenacious and predatory flora had adapted to this inhospitable environment—gnarled organisms capable of thriving where gravity itself seemed to falter. In many respects, the moon resembled a Death World. None of this had prevented the Mechanicum from establishing research complexes, designated according to the atypical nomenclature Templum X Logicies Y, which would translate into modern Gothic as "temple of programming." When the Adeptus Mechanicus recovered these facilities, they declined to share either the exact nature of the work conducted there or the reason for such a concentration on a single moon. Some claimed that the Lords of Mars themselves had no idea.

One of the rare pieces of knowledge that Inquisitor Nadre Bredasson managed to glean referenced a certain Magos Gero. During the Horus Heresy, they had allegedly taken command of all the Templum Logicies. All would then have concentrated their research on means of communication independent of the Noosphere. It also seemed that this pivot in the research conducted on Harpax III came following contact with a Standard Template Construct fragment—whatever that might have meant.

Ancient Echoes, Moving Shadows

Perhaps these rumours had been fuelled by the presence of archeotech around Harpax. Indeed, while the planet's other satellites were uninhabitable, surveys conducted after the system's 'rediscovery' indicated traces of ancient occupation. Three moons in particular—caught in a singular orbital resonance—bore architectural remains whose origin was undetermined. Some recognized in them the mark of the Aeldari, others an even more sinister imprint.

Galarn Martagot had undoubtedly consulted these same surveys, for his flotilla kept prowling around the gas giant despite the perils this represented. Such behaviour had surprised Archmagos Gabatine, who had expected the Rogue Trader to rush toward the neighbouring Forge World to plunder all its treasures. What greater marvels had he scented here?

This prolonged presence around Harpax was not without risks, however. The asteroid belt that cluttered the giant's orbit served as a haven for pirates—human for the most part, though a few reports spoke of raids far too cruel and too precise to be the work of simple void scavengers.