Ruins of Surmia (quest)
BONUS: Exterminate the Flame Keepers
The trick to this is to allow the Ember Keepers to pass unattacked. They will march quite a long ways west, opening up a couple of gates on the way. Follow behind them without setting off their aggro. Eventually they will lead you to the Flame Keepers you need to fight. There are four of them, and they will be level 7.