I know what must be done!  $N, you must pose as Overseer Nuaar and attend that meeting!$B$BThe wyrmcultists at the coven all have a standard outfit that they wear, so go collect scraps from them, and when you have enough, put together a disguise.$B$BPose as Overseer Nuuar and speak with Kolphis Darkscale to see what he has to say, and then return to Tree Warden Chawn.$B$BYou'll find the coven by heading through the Wyrmskull Tunnel and following the path past the Raven's Wood and Grishnath to its end.