The Dramya are a group, perhaps a species, alluded to by Trade Master Greenish of the Melnorme during his negotiations with The Captain of the New Alliance of Free Stars. If The Captain attempts to assert The Flagship's military superiority over Greenish's Inevitably Successful in All Circumstances, Greenish invokes the Dramya as a quiet threat, claiming that the Dramya civilization had once attempted to steal from the Melnorme, and pointing out that you don't see many Dramya around these days. This assertion, if true, indicates that the Melnorme, though apparently small in numbers in this part of space, are no easy prey. Whether this supposed military capability comes from the Melnorme themselves, or from mercenaries, is not mentioned.
On the other hand, the Dramya might just be made up by the Melnorme to deter The Captain from attacking.