...the Changling found his way barred: not by the embattled heroes, but by a diminutive figure that was hidden entirely by white robes and carried a graven crozius in both arms. The Daemon recoiled in horror, for the creature before it was anathema to its kind. The creature focussed its baleful glare, and the Changeling turned and fled.
Wrath of Magnus, page 29.
So, what are these little guys? I'm aware of their history fighting the chaos taint on Caliban, but this is the first time I can remember anything other than the Emperor being called anathema to demons. Could they just be a race of pariahs? Or are they something more? What do people think?