The Waterdhavian creatures are the four creatures from Waterdeep that were needed to cure the plague in chapter one of the original campaign. Specifically, the creatures are a cockatrice, a dryad, an intellect devourer, and a yuan-ti. Spoiler warning: Plot and/or ending details follow. The cockatrice is regrettably killed before the player can locate it. Fortunately, all that is needed from it is a feather, which can be found where it was killed, in the Docks District. The dryad can be found in Blacklake, held captive by Meldanen. The yuan-ti took refuge in the Beggar's Nest.