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
contested
Ice-bound by Chaos; rebellion and Imperial withdrawal
Once a productive Imperial world with hive cities such as Alpha Hive and Iota Hive, Cressida has been gradually turned into an ice world by the influence of Chaos, and a Chaos-fuelled rebellion has overrun it. The Valhallan Ice Warriors of the 319th and the Royal Validians of the 14th fight a losing battle to hold the Chaos forces back while as much of the population as possible is evacuated. In Ice Guard the withdrawal has been ordered, and Colonel Stanislav Steele's Valhallans are sent into a Chaos-held city after a stranded Imperial dignitary while the battleships in orbit prepare to virus bomb the world.
Era Indomituspost-Rift
[RECORD LOST]
No record for this location in Era Indomitus.
Position
Map frame: 791, 827.6 in the archive's 0–1000 disk space (core at 500, 500).
Distance from the core: 438 units ≈ 46.6k light years, south-east of the galactic core.
Height above the disk plane: 0.8 units — invented thin-disk jitter, deterministic per record. No published source gives any location a z coordinate.
System: Cressida 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/Cressida (read directly in a browser on 2026-10-02): 'Cressida is a Dead World that was the site of a Chaos-fuelled rebellion'; 'Once a productive world, Cressida was gradually transformed into an Ice World by the influence of Chaos'; the Royal Validians and Valhallan Ice Warriors 'fought a losing battle to hold the Chaos forces at bay while as much of the planet's population was evacuated', all cited to Ice Guard (Novel). https://wh40k.lexicanum.com/wiki/Ice_Guard_(Novel) (read 2026-10-02): Black Library's description, 'the ice world of Cressida'. https://wh40k.lexicanum.com/wiki/Royal_Validians (read 2026-10-02): the 14th Royal Validian helped evacuate Imperial citizens from Iota Hive to Alpha Hive (Ice Guard, Hammer of the Emperor p. 406). NAME-COLLISION CHECK: Lexicanum's full-text search for 'Cressida' returns this one world; the other hits are a Shakespeare allusion and a person in the Cytos Cartel article. No other index record uses the name.
classhigh
'ice' from what the sources say it LOOKS like in the novel: 'the ice world of Cressida' (Black Library's description) and 'transformed into an Ice World by the influence of Chaos' (Lexicanum Cressida, filed under Ice Worlds). The infobox's 'Dead World' is the state the world is left in at the novel's end, a catastrophe the book's pages race against rather than show, so it is refused as the look (ADDING-A-BOOK Step 5a2: an era gets the state most of its books are set in).
segmentumhigh
wh40k.lexicanum.com/wiki/Cressida null: infobox Segmentum, Sector, Subsector and System all 'Unknown', filed under Segmentum Unknown (read 2026-10-02); no other permitted source places it.
gposlow
inferred: no published segmentum, sector, subsector or bearing. No segmentum is claimed; unsurveyed rim, no positional information. [791.0, 827.6] is build_locations.py rim_xy('cressida') (the function's arithmetic reproduced and checked against khadar's [644.8, 928.9], rogar-iii's [211.5, 165.0] and jumael-iv's [205.2, 822.6], the script not run); Z 0.8 from compute-z.mjs under zPolicy.
erasmedium
Only 'm41' is carried: Ice Guard (January 2009) is undated in every permitted source (Lexicanum Valhallan_Ice_Warriors lists the Cressida Rebellion among its undated battles, citing the novel's chapter 2), and the shelf files it M41 — Pre-Great Rift with the rest of the classic Imperial Guard run. 'contested' because the Imperial Guard and the Chaos rebellion fight for it. The world's state after the novel is its ending and lives in the catalogue spoiler, not on the map; planets never vanish, so other eras fall back to the base class.
systemIdlow
editorial: 'cressida', the world's own name, because Lexicanum's System field is 'Unknown' and no permitted source names a star or a system. systems/cressida.json is a one-body TRUNCATED survey, authored because this is the novel's PRIMARY setting.