In a mirror universe, a Terran Empire starship, Galaxy-class attack cruiser, Empire registry NCC-1701-D. In one possible permutation of the mirror universe timeline, this vessel was commanded by Jean-Luc Picard. (TNG novel: Dark Mirror)
- Dark Mirror was published prior to the Star Trek: Deep Space Nine episode "Crossover," which presented a very different version of the 24th century Mirror Universe (first seen in TOS's "Mirror, Mirror"). As such, data points from Dark Mirror have (so far) been ignored in subsequent fiction.