The only time you enter this place is for the related quest instance.
-  Vol. 1, Book 12 -- Instance: Weapons of the Enemy - Fellowship
The following creatures are found within this area:
- "Plagued by terrible dreams in the House of Elrond, Laerdan reveals in his sleep that Amarthiel's ring, Narchuil, is being held in the fastness of Barad Dúrgul." — Instance Text