4 keys
(you find them by killing Demon at Temple),
then visit the NPC of your profession and combine those
4 keys
to generate a 
master key.
Next, venture to 
Neverwinter. Board the ship and seek out the NPC Naak there.
Bring the master key with you, and when you speak to him,
he will take the master key and summon Naak in the city. 
Doodler Jungle.
It's random. However, if you defeat him,
there's a very high chance he'll drop 
Black items!