Overview
Stormy oceans cover most of Talassar. Its cities and fortresses occupy Glaudor and rocky islands, with journeys between them dependent on water that has its own reasons for killing travellers. Noble houses hold traditions of service to the Ultramarines alongside their other claims to authority.
Cato Sicarius is among the warriors those families produced. Titles and inherited weapons preserve the connection between a soldier and the world he left. Talassar has also been invaded, occupied and recovered. Its military heritage does not spare the people living beneath its fortresses from becoming the reason another generation of warriors must return to fight.
History
During the Heresy, Talassar’s recruiting facilities and stored gene-seed attracted raiders. Night Lords occupation followed the Shadow Crusade. A Blood Angels-led operation recovered genetic material before the Ultramarines eventually retook the world.
Military significance
Castra Tanagra commemorates a victory over orks early after the Heresy. In late M41, the struggle against M’kar brought Calgar, Sicarius and Ventris to Talassar. Recruitment and inherited military standing have repeatedly made the world an objective as well as a source of defenders.
M41 and M42 status
Imperial ocean world
Talassar remains inhabited, with cities and fortresses on Glaudor amid its stormy seas. Its connection to the Ultramarines rests on living institutions as well as the ancestry of famous warriors.
Void Tridents Chapter homeworld
The Ultima Founding gives Talassar to the Void Tridents as their homeworld. That new Chapter relationship follows the older Ultramarine heritage. No complete census or reconstruction report is established.
Timeline
Night Lords occupation and the Castrum Velx raid disrupt Talassar.
The struggle against M'kar reaches its conclusion on Talassar.
Talassar becomes the homeworld of the Void Tridents.
Related charted locations
Administrative record
Tithe grade: Not established
Population: Not established
Chart placement and sources
Provisional placement
Heresy-era prose places Talassar in southern Ultramar; the current official Inner Ultramar diagram places it west and slightly north of Macragge.
Southern Ultramar is a regional description and does not mean south of Macragge.
Official 2026 system diagram. The retained Macragge anchor and an editorial scale fit the local diagram into the existing Ultramar region. Relative layout is reproduced; physical distance and exact galaxy coordinates are not measured.
- Lexicanum — Talassar — Secondary reference
Book references indexed by this source: Codex: Ultramarines, p. 14; The Chapter's Due, chapters 9, 12, 23–24; White Dwarf October 2017, p. 118
- Warhammer Community — Assault on Castrum Velx — Official source
Book references indexed by this source: Exemplary Battles of the Age of Darkness: Assault on Castrum Velx, pp. 2–3
- Warhammer Community — Cato Sicarius, Captain of the Victrix Guard — Official source
- Warhammer Community: Inner Ultramar diagram, 11 February 2026 — Official source
- Void Tridents — Lexicanum — Secondary reference
The dossier is available offline. Reference links open external websites.
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Cartographic positions and several administrative details are intentionally approximate where published Warhammer sources conflict or provide no canonical coordinate system.