Slay 20 Noxious Plaguebats and 10 Monstrous Plaguebats. Return to Nathanos Blightcaller when you are finished.
You cannot take two steps off of this farm without running into one of those obnoxious bats. I want to be able to take the hounds out and slaughter Scourge without being accosted by any damned, dirty bats. Obviously, I have better things to do with my time than mindlessly kill bats day in and day out. You, however, do not.
What? Your training? This is your training! Now get out of my sight and don't come back until you've killed a fair number of those winged demons. Don't disappoint me.