Using the Purified Moon Well Water, douse the flames of the four braziers of protection within Shadow Hold in Felwood, then return to Greta Mosshoof in the Emerald Sanctuary.
Now, you must return to Jaedenar. The braziers are more than likely spread throughout Shadow Hold. Douse each of their flames and the protections the Council has set up will fall for at least a short period of time. I will be waiting for that to happen. When it does, I will look deep within the Hold and try to find out who the head of this beast is. Then, and only then, will we see about attacking them directly.