This archive tracks four layers. A record present in 2 of them (M41, IND) 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
Hive world; home of the Mordian Iron Guard
The World of Eternal Night: a tidally locked planet whose hundreds of millions live crowded on its dark side, in pyramidal hive cities rising like mountains, under a Tetrarchy that rations everything. Discontent is bred into it, and the Iron Guard regiments it raises are what stand between order and anarchy. Iron Guard opens in its hive gangs, where a sergeant of the 114th collects the regiment's tithe of recruits.
Era Indomituspost-Rift
contestedImperium Nihilus
Besieged by the Thousand Sons; stranded in the Dark Imperium
Cut off on the far side of the Great Rift, Mordian was besieged by the Thousand Sons during the invasion of the Stygius Sector. The Stygius Crusade broke the siege but could not hold the sector, and the world is held against Chaos with the help of the Iron Hands, while sorcerers, Harlequins and Necron lords contest it.
Position
Map frame: 545, 215 in the archive's 0–1000 disk space (core at 500, 500).
Distance from the core: 289 units ≈ 30.7k light years, north of the galactic core.
Height above the disk plane: -4.1 units — invented thin-disk jitter, deterministic per record. No published source gives any location a z coordinate.
System: Mordian System
Books set here
2 titles in the reading tracker touch this record. 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/Mordian (read directly in a browser on 2026-10-02): 'an Imperial Hive World that was renowned as the home world of the Iron Guard Regiments of the Imperial Guard'; tidally locked, all life on the dark side, 'the World of Eternal Night', pyramidal multi-level hive towers, the Tetrarchy (Codex: Imperial Guard 5th ed. p. 16; White Dwarf 184). NAME-COLLISION CHECK: no other index record uses the name; on Lexicanum 'Mordian' is this world and its regiments.
segmentumhigh
wh40k.lexicanum.com/wiki/Mordian infobox: Segmentum Obscurus (Codex: Imperial Guard 5th ed.), Sector Stygius Sector, System Mordian System (Warhammer 40,000 8th Edition Rulebook pp. 164-165, War Zone: Stygius); filed in Category Segmentum Obscurus. https://wh40k.lexicanum.com/wiki/Stygius_Sector: a sector 'in Segmentum Obscurus and Ultima Segmentum', listing the Mordian System as Imperium-held.
gposmedium
derived: Segmentum Obscurus, in the Stygius Sector, which Lexicanum places across Segmentum Obscurus AND Ultima Segmentum, and on the Imperium Nihilus side of the Great Rift (Lexicanum Category Imperium Nihilus; 'one of the worlds which became stranded in the Dark Imperium'). Placed just on the Obscurus side of our Obscurus/Ultima seam in regions.json (the seam runs (600,186)-(520,262); at y 215 it is at x 569.5), well north of the Great Rift line (y about 328 at x 545), so the record sits where the sector's two published facts meet. No bearing within the sector is published. Z -4.1 is the zPolicy value (compute-z.mjs mordian 545 215).
classmedium
'hive' from what Lexicanum says it LOOKS like: hive cities of 'pyramidal, multi-levelled towers rising like mountains towards space' crowded onto a land surface a tenth the size of Earth's, on the night side of a tidally locked world; here the infobox (Hive World) and the description agree. 'dead' and 'ice' were refused: the sun-burned day side and the frozen dark side are the setting of the hives, not their look.
erasmedium
m41: the Codex: Imperial Guard 5th ed. description and the Iron Guard regiments (Lexicanum Mordian). indomitus: 'stranded in the Dark Imperium', besieged by the Thousand Sons during the Invasion of the Stygius Sector, the siege broken by the Stygius Crusade, held against Chaos with the Iron Hands and their successors (Codex Supplement: Iron Hands 8th ed.), and contested by Khethos Vorsch, The Vessel, Rillietann, Serevakh and Trazyn (Warhammer Community Grand Narrative 2025, as cited by Lexicanum). riftSide nihilus from Lexicanum's Category Imperium Nihilus. The Battle of Mordian against the Chaos invasion (White Dwarf 184) is undated and is carried by neither era. hh and aoi carry nothing.
systemIdhigh
'mordian' from Lexicanum's infobox (System: Mordian System). No systems/mordian.json: Mordian is a VISITED setting of Iron Guard (its Prologue), not the book's primary, and the only body Lexicanum names beyond the world is the void station Solemnity's Might in geostationary orbit (2025 Grand Narrative). The map synthesises the globe from this record.
iron-guardhigh
wh40k.lexicanum.com/wiki/Iron_Guard_(Novel ) (read directly in a browser on 2026-10-02), synopsis, Prologue: Fernand Hool, eighteen, in 'the endless gang rivalries of the hive city on Mordian he has never set foot outside', is taken by Sergeant Polk of the 114th Iron Guard as part of the regiment's tithe of new recruits. Black Library's description on the same page: 'The 114th Mordian Iron Guard, pride of their world'. Joined VISITED.