: The Eastern Dwarfs is a book series about the four dwarf houses in the far east of Middle Earth.
The Dwarf Lords proved resistant to the malevolent magic of the rings, which could not even turn them invisible. The rings amplified their wearer's natural skills and desire of dominion which as a consequence, they became greedy and exceedingly rich; the Rings gave them the power to multiply whatever they mined.
Angered by his failure, Sauron tried to gather the rings back to him. He succeed in finding two, while four others were swallowed or destroyed by Dragons. The third ring Sauron obtained was taken from Thráin II in T.A. 2845 while he was imprisoned by Sauron in the dungeons of Dol Guldur. Gandalf arrived too late and only got the key and Thrór's Map to the secret entrance of the Lonely Mountain from Thráin.