dol guldur

Dol Guldur, also known as the Hill of Dark Sorcery, was Sauron's stronghold and base of operations when he worked his sorcery in the wood under the name of The Necromancer. It was located in the south of Mirkwood for over twelve-hundred years in the Third Age.

 

Some believe that before Sauron returned to the fortress a rare species of creature called the Mewlips took up residence in its cellars and underground passages.