"Work harder you lazy karkers! This shrine must be erected by tomorrow, if we want to honor the day of redemption! Give it your all and then some, unless you seek to become food for the poxwalkers!"
A cultist that seems a bit less bothered by his plagues than the others seems to be overlooking a few sickly hivers turned slaves, as he walks up and down, watching them build a shrine to Nurgle. He doesn't seem to be all too kind to them, but he doesn't stab at them with the bayonet of his shotgun either... At least not more than necessary. Can't have them not toil away for the glory of Nurgle after all.
Some of the slaves themselves seem to be suffering from the "gifts" of chaos, judging by the many signs of mutation most of them have to show openly because of a lack of rags to hide the rather large malformations. The fact that these slaves are allowed to keep a somewhat free will and aren't turned into poxwalkers yet shows that the cult probably seeks to make them the first sacrifice, once the shrine is built.