The purple-clad intruders in Craftsman's Rest are well known to the Harpers. They are members of the Cult of the Dragon, a group dedicated to restoring control of the world to dragon overlords. Whatever brings them here, we can be certain that it bodes no good for Neverwinter.
The Cult of the Dragon does not usually operate so openly. Defeat them and search them for orders. If you can collect enough, I should be able to crack their code.