Agatha the Banshee
Agatha was an elf who became obsessed with her own beauty and is now an undead, doomed to live in the southern Neverwinter Woods. She was, however, looked after by the people of Conyberry until the village was ransacked by Barbarians.
She was visited by the Harlequins who gave her a silver comb in return for information on how to find the Wave Echo Cave near Phandalin. They even parted on decent terms with a proposal that if the Harlequins sought a quest and she sought something she could not get (she could only go up to 5 miles from her lair) then there might be a mutual interest. Agatha had great local knowledge and could assist in finding treasure etc.