User blog comment:Zathronas/Analysis by an author: Volume 2 episode 2/@comment-11188061-20140801011606/@comment-11188061-20140801013937

We are told that the Grimm will show what they're capable of this Volume. Qrow is dropping signs of doom serious enough that Ironwood brought hundreds of soldiers to support Ozpin during a festival. Not even a concerned friend goes that overboard unless he has serious cause to worry about.

And since I don't believe they're referring to the Faunu, and Cinder's faction is still underground, the obvious points towards the Grimm.