User blog comment:Maki Kuronami/Lesson 27: Screw everything, have a Samurai!/@comment-4010415-20141024045439/@comment-9090085-20141024051931

except the ones we've seen are similar in size  and numbers to Beowolves (look at the scenes where the Grimm are running through the tunnels.

Not saying they aren't dangerous, though.