Board Thread:Speculation House/@comment-4830106-20130810030606/@comment-24198837-20140509211100

Of course. If it turns out that Grimm are just glorified animals, then using them in combat would be akin to using Horses as mounts or war dogs - which aren't evil tactics.

I'm just going off what Pyrrha said regarding aura, and what Jen said in the opening exposition dump, that "...they are the darkness..." and are "...intent on returning mankind... to the void".