Fighting the Infestation

Note
The first time you hail the Commissioner after completing Once upon a Plague he'll give you the quest in this writeup. Once you complete it and hail him again, you'll get a new quest by the same, Fighting the Infestation.

Steps
First time through the quest (level 36):
 * 1) Kill 10 corrupted brigands

This completes the quest the first time through. Hailing the Commisioner again will result in him asking you to fight more infestations.

Second time through the quest (level 39):
 * 1) Kill 10 darkflight reapers

Rewards

 * Experience
 * At least (first time through)
 * At least (second time through)