Isstvan Extremis

Isstvan Extremis is the outer augury-nexus of the Isstvan system, silenced at the opening of the Isstvan III Atrocity. An augury-nexus is a cluster of detection and early-warning installations that monitors approaches to a star system.

Horus arranged for the Emperor’s Children and the Death Guard to silence the installation so that the inner worlds of the system could be blinded before the virus-bombing of Isstvan III. In the opening skirmish of the Atrocity, the Warsinger outposts stationed there were destroyed, together with the early-warning equipment they operated.

Isstvan Extremis has no separate treatment in most reference works. Its status is recorded briefly within the entry for the Isstvan system, and the assault upon it is named in the account of the battle of Isstvan III. Its loss marks the first stage of the operation against the system.