Revolution
The uprising and period of civil unrest within Tertium caused by the Pit Rats. 401st Novarian Regiment dispatched to crush the rebellion after Adeptus Arbites forces proved unsuccessful. Astra Militarum forces successfully scattered the underhive force, but the chaos caused by the uprising led to chaos within their own ranks. The Pit Rats capitalised on the disorder and were able to deal significant damage to the superior forces of the Imperial Guard.