This archive tracks four layers. A record present in 1 of them (M41) is silent in the rest, and says so.
The Horus HeresyM30–M31
[RECORD LOST]
No record for this location in The Horus Heresy.
Age of the ImperiumM32–M40
[RECORD LOST]
No record for this location in Age of the Imperium.
The 41st Millenniumpre-Rift
imperium
Imperial agri world on the Eastern Fringe, threatened by a tendril of Hive Fleet Gorgon
An Imperial agri world of the Styxia system on the Eastern Fringe, with a single city. Late in M41, in the years after Ichar IV, a tendril of Hive Fleet Gorgon falls on it; the Cadian General Arka fortifies the city with the Cadian 308th, the Astcarian Fourth and the Titans of Legio Fortitudis, and Chaplain Ortan Cassius brings an Ultramarines strike force to its defence (Catechism of Hate).
Era Indomituspost-Rift
[RECORD LOST]
No record for this location in Era Indomitus.
Position
Map frame: 860, 560 in the archive's 0–1000 disk space (core at 500, 500).
Distance from the core: 365 units ≈ 38.8k light years, east of the galactic core.
Height above the disk plane: -9.4 units — invented thin-disk jitter, deterministic per record. No published source gives any location a z coordinate.
System: Styxia System
Books set here
1 title in the reading tracker touches this record, 1 of them as a primary location. Titles link out to the tracker.
Every fact in this record, and where it came from. Editorial derivations say so.
identityhigh
wh40k.lexicanum.com/wiki/Styxia_Prime (read directly in a browser with fetch-page.mjs, 2026-10-05): 'Styxia Prime is an Imperium Agri World located in the Eastern Fringes that was once threatened by a tendril of Hive Fleet Gorgon' (Catechism of Hate ch. 2); 'Under the command of the Cadian General Arka and the Ultramarines Chapter's Master of Sanctity Ortan Cassius' (ch. 2). Infobox Segmentum: Ultima Segmentum; Sector and Subsector Unknown; System: Styxia; Affiliation: Imperium; Class: Agri World. Sole source: Catechism of Hate (Novella). Black Library's own page (Internet Archive, 2012-2017) says 'the world of Styxia'. NAME-COLLISION CHECK: no index record uses the id, the label or 'Styxia'; Lexicanum has no other Styxia page.
book-joinhigh
PRIMARY for Catechism of Hate: its defence is the novella's subject (Black Library's description; Lexicanum Styxia_Prime, Arka, Dacia_(Ultramarines), Fidelis_(Strike_Cruiser), Astcarian_Fourth, Legio_Fortitudis). The outcome is kept in SPOILERS, not here.
segmentumhigh
ultima: Lexicanum Styxia_Prime infobox 'Segmentum: Ultima Segmentum' and text 'located in the Eastern Fringes' (categories Eastern Fringe, Ultima Segmentum); the Eastern Fringe is the outer edge of Ultima (regions.json outerRegions 'eastern-fringe').
classmedium
'agri': Lexicanum's Class is 'Agri World', and here the tag and the look agree, because an agri world is farmland (unlike a hostility tag such as Death World). The only terrain fact on any page read is that it has a single city (Lexicanum Arka, ch. 2: 'the world's only city'), which fits fields around one settlement. No colour words; revisit if a source describes the land.
gposlow
inferred: region-level. Canon gives Ultima Segmentum and the Eastern Fringe and nothing finer. Hive Fleet Gorgon's theatre is the Eastern Fringe (Lexicanum Gorgon_(Hive_Fleet): 'Location Eastern Fringe'; it invaded the T'au Empire and 'has begun to re-establish itself on Imperial Agri-worlds'), and General Arka's regiment came on from the aftermath of Ichar IV (Lexicanum Arka, ch. 2). Placed at (860, 560): inside the 'ultima' polygon, east of the Eastern Fringe label (790, 410), south of the T'au sept markers (Dal'yth 880, 470) and east of Ichar IV (710, 512); nearest other marker Solemnace at 36 units. No distance or bearing is published. Z -9.4 is the zPolicy value (compute-z.mjs styxia-prime 860 560).
erashigh
m41 only: the novella is set after Ichar IV (993.M41, the opening of the Second Tyrannic War; Lexicanum Arka ch. 2, List_of_Battles_of_the_Ultramarines) and 'in late M41' (Lexicanum Legio_Fortitudis, Epilogue). Allegiance 'imperium'.
systemIdhigh
'styxia': Lexicanum Styxia_Prime infobox 'System: Styxia'. Surveyed in systems/styxia.json as one world, TRUNCATED.