The Ordo Xenos refers this matter to the Celestial Questors Chapter on the basis of their operational presence in the Ultima Segmentum. The Chapter is asked to treat this intelligence as preliminary. Full disclosure of supporting materials remains subject to Inquisitorial review.
Over the last several decades, multiple separate incidents across the segmentum have produced evidence of unknown xeno-organism activity. The organisms involved bear sufficient morphological similarity to be treated as related pending further investigation. Their origin is unknown. They do not match any entry in the current Ordo Xenos biological registry. The Ordo has provisionally designated this organism cluster Hive Fleet Stygian. A working classification only.
Genestealers are a known quantity. What is not known is what they are doing here, and in whose company. The specimens recovered at Ossuary-Trine display a colouration typical of catalogued example. Dark, almost black chitin with a faint blue iridescence along the plating and vibrant violet skin. Their presence, combined with a pattern of suppressed incident reports and unexplained disappearances at a second site, is consistent with Genestealer infiltration preceding a larger incursion. The Ordo emphasises this connection is unconfirmed.
A third incident is of greater concern. Mining Station "Vault-Cradle Secundus" went dark in ~651.M41. Survivors within a supply barge vessel that escaped to Warp provided detailed sketches and descriptions of a second organism before their sanctioned termination. Larger, bipedal and heavily armoured in natural chitin, they engaged with crew members through the use of a variety of ranged and close-quartered natural weapons. It resembles the Genestealer in number of limbs, colouration and skull shape. It does not resemble anything else currently classified.
The organism moved with deliberate unhurried purpose, pausing at intersections, surveying its environment before advancing. Whether this reflects individual intelligence or direction from an external source is unknown. The morphological kinship between this organism and the Genestealer specimens may indicate a common origin. The Ordo does not speculate beyond the evidence.
The Celestial Questors are asked to report any sightings of organisms matching these descriptions within their operational theatre. Should the Chapter encounter either organism in force, the Ordo requests vox-contact with Sable-Noctis before engagement where possible. Live specimen recovery would be of considerable value to ongoing investigation.
Whatever is behind Hive Fleet Stygian has been patient. It has been here longer than we know. The Chapter is advised to proceed accordingly.