One of Thorin Oakenshield's supporters in the quest to regain the Lonely Mountain from the great worm Smaug, Balin subsequently moved to the old Dwarven stronghold of Moria in the Hithaeglir in an attempt to wrest it back from the orcs. The enterprise proved ultimately disastrous as the small Dwarven band succumbed to the great number of their foes and to the growing threat of the terrible Balrog, which had awoken below.