One of the seven houses of the Dwarves, the Blacklocks dwelt in the far eastern mountains of Middle Earth, possibly the Orocarni mountains where the Fathers of the Dwarves awoke. Despite their remoteness, they still maintain trade with the Dwarven clans of the Iron Hills and Erebor and sometimes send troops to the aid of their kin in times of need. However, the allegiance of the Eastern Dwarves is not always certain. While it is likely that many came to the aid of their kin in the War of Dwarves and Orcs, some also fought for the Dark Lord in the war of the Last Alliance at the end of the second age. Souron's hold over the eastern regions of Middle Earth is not well known, but it is certainly greater than in most regions of the West.

The Blacklocks use their short stature in conjunction with the superior range of their long pollarms to deliver blows against taller enemies from as far back as the second and third ranks. In this way, they are able to devestate enemy infantry formations while the second and third rankes remain shielded from retaliation similarly to a phalanx. The Blacklocks do not make use of shields and are vulnerable to arrow fire and charges of heavy cavalry.