Editing The Purge

The Purge are a warband of Chaos Space Marines following the ways of Papa Nurgle and were last seen spreading his special kind of love during a holiday on the planet of Vraks. They are in possession of some ridiculously powerful chemical weaponry that can dissolve a guardsman whole and given time has major problems fucking up a Leman Russ or Macharius tank too. Like I say... ridiculous. We haven't really heard a whole lot of them beyond that (if anything) and they didn't even play a particularly large part in what was a fuckhuge and exceptionally grimdark war. They stalled a major offensive or two, but primarily that was because even the psychotically loyal and brave men of Krieg can't keep fighting when they are being dissolved by the aforementioned chemical weapons, although any commissars present probably tried to make them. Given that the offensives stalled out, with crazy huge casualties even by the standards of the Vraks conflict (where it was assumed that the sixth wave of twenty thousand would reach the enemy by constructing a crude armored vehicle from the remains of the first five waves) we can only assume that those commissars were unsuccessful, and/or their hats dissolved and thus robbed them of any authority. 

The main reason why the Purge are memorable beyond slaughtering Kriegian guardsmen is that the areas that they fought on are even more uninhabitable than the rest of the quagmire of corpses, promethium and undetonated shells that is Vraks. So that's gotta count for something?