World · Segmentum Ultima

Diamat

Fig. 1 · Location on the map

Diamat is an isolated super-forge world of the Tanagra system (Segmentum Ultima) on the edge of the Ulthoris sub-sector, only 52.7 light years from Isstvan. The Battle of Diamat (005.M31) is a very early clash: the Dark Angels of the Lion against the Sons of Horus for siege engines later seized by Perturabo.

Category: World
Location: Segmentum Ultima
Significance on the map: 2 of 5
Place confidence: Place reliable
Events: 1 event

Place on the map

Grounds for placing the system exactly here on the map:

«Diamat… Tanagra System, Segmentum Ultima… just 52.7 light years from Isstvan» — Atlas compilation · source check 2026

Events in the system

Battle of Diamat 005.M31 · Loyalist victory

Legions

Legions named in the system’s events:

I Dark Angels 1 event
XVI Sons of Horus 1 event

Factions

Named among the sides of the system’s events:

Imperial Army 1 event
Dark Mechanicum Mechanicum · 1 event

Characters

Linked to the system’s events:

Corswain “the Seneschal” Champion · Legion I · 1 event
Lion El’Jonson Primarch · Legion I · 1 event

Sources

Lexicanum: Battle of Diamat
WH40k Fandom: Battle of Diamat
Atlas compilation · source check 2026

Open in the atlas

Permalink: https://astart.es/en/systems/diamat/