aberrations

i think that all aberrations should share a fluff--with varying mechanics--whereby their mere presence is anathema to their immediate environment. different sources of inspiration for this include the starcraft zerg and dark sun defiling. this fluff would lend further credence to the imperative sentiment against the far realm and its progeny, especially among the primal forces of the world.

such fluff would cause aberrations to stand out among the other threats to the natural world and the "natural order of things." a primal character might consider the undead to be an affront to the natural cycle of life; he might combat creatures of the elemental chaos because of their conflicting values of creation and recreation; but, that primal character would regard the mere existence of an aberrant creature as a cancer upon his sacred world.

one example that i have considered is having the caves of a grick colony coated with a strange substance (think zergs or aliens the movie).