War for the Ulmetrican Reach
In the last years of M31, Clan Raukaan was deployed into the Ulmetrican Reach. Supported by elements of Companies Clan Avernii and Clan Dorrvok and led by 4 Iron Fathers, this massive force was charged with crushing the rebellious factions that had spread throughout the system. What had begun as a workers’ uprising on the factory moon of Tholsh had spread through the reach, swiftly taking on overtones of dark worship and fanaticism. Yet when the Iron Hands translated from the Warp to begin their war they found that their foe was cunning enough to evade open battle. Rather than stage full-scale armed rebellions, the cults were remaining well underground. They used powerful psykers to communicate with one another, and to influence the governors of the worlds they had infested. Initially, Iron Captain Morlus commanded his forces to strike with surgical precision – the Scouts of Clan Dorrvok were deployed on key worlds throughout the reach, sweeping mile by mile with machine-like patience in their search for cultist cells. As each such canker was located, teleport attacks and Drop Pod assault were used to bring massive force to bear and exterminate it completely.
Yet almost a year of this approach seemed to bring the Iron Hands no closer to victory, the foe’s numbers still unknown. Repeatedly, the bravest Cultists used makeshift anti-orbital missiles to strike at Clan Company Raukaan’s ships. With no clear enemy to confront, the majority of Clan Raukaan could do little but train and wait for an opportunity to deploy. Matters came to a head when, on the hive world of Pulus, several corrupt shrines were discovered. These foul, fleshy monuments gave praise to a Slaaneshi Daemon, named by its worshipers as the Sapphire King. From that moment, the entire character of the war in the Ulmetrican Reach changed. The Iron Fathers met in conclave and determined that they had no choice but to declare the entire populace of the region guilty of the same kind of corruption that had twisted Fulgrim during the Horus Heresy. That the vast majority of the reach’s populace were not deemed directly responsible was neither here nor there – these supposed innocents had allowed a foul cancer to take root in their midst, and must be punished accordingly.
Thus with a single command, the Iron Fathers launched a six year war of extermination that saw a system-wide genocide. Eventually the Iron Hands were successful and cleansed the system of Slaanesh's taint.