I have added a short summary of how to deal with Nethermancer Sepethrea – second boss of Tempest Keep: Mechanar dungeon-wing.  She is located at the second floor once you use the elevator.  This boss can be pretty hard if you fight her for first time.  Hopefully the tidbits shared here will boost your learning curve.  Don’t miss the video at the bottom.  We took her down in 2:32 minutes.