Despite being officially independent of the Imperial state church, the Ghreddask Illuminators are known to enforce the will of the Ecclesiarchy within the Talledus System.
For instance, the orbital dockyards at the world of Satrapol in the Talledus System were amongst the largest in the Imperium. Thousands upon thousands of vessels were packed together in cramped mooring claws, kept stationary for Terran months and sometimes even years as the Ecclesiarchy's agents methodically ensured that every vessel paid a tithe to the church. Those who failed to pay what was owed, or in any way roused the ire of the state church, were dealt with by the ruthlessly zealous Ghreddask Illuminators.
The most heavily defended world in the Veritus Sub-sector after the capital planet of Benediction itself, Ghreddask supported many regiments of the Ghreddask Illuminators deployed in large garrisons as well as other potent planetary defences.
It nonetheless was invaded during the Talledus War by the Iron Warriors under the command of Warpsmith Etrogar, who used a spaceborne Soul Harvester fortress-factory called Scarax Krond to devastate the planet.
The tide only turned thanks to the intervention of Castellan Dramos of the Black Templars' Rutherian Crusade, who sacrificed himself to destroy the unholy Daemon Engine and give the Astra Militarum forces of Ghreddask a fighting chance against the Heretic invaders.
- Psychic Awakening - Faith & Fury (8th Edition), pp. 16-17