The Mirror Universe was ruled by Regent Worf (Michael Dorn) during the 24th century, as seen in Star Trek: Deep Space Nine. DS9 brought back the Mirror Universe in a big way, starting with the season 2 episode “Crossover”, in which Major Kira Nerys (Nana Visitor) and Dr. Julian Bashir (Alexander Siddig) found themselves in Star Trek‘s darkest timeline. Interestingly, the original plan for “Crossover” was to have Michael Dorn make a cameo as his Mirror Universe counterpart, but he was unavailable due to filming commitments on the final season of Star Trek: The Next Generation.
When Star Trek: The Next Generation‘s Michael Dorn joined Star Trek: Deep Space Nine full time in season 4, he got a chance to play his Mirror Universe counterpart in the episode “Shattered Mirror”. TNG never did a Mirror Universe episode, so Worf holds the distinction of being the only member of the USS Enterprise-D to have a dark alternate. Worf’s role in DS9‘s Mirror Universe episodes was a substantial upgrade from the Klingon solider that he would have cameoed as in “Crossover”, because he was revealed to be the ruler of the entire Mirror Universe.
Star Trek: Deep Space Nine revealed what happened to the Terran Empire after the Star Trek: The Original Series episode “Shattered Mirror”. The peaceful reforms brought about by Mirror Spock (Leonard Nimoy) ultimately led to the fall of the Terran Empire at the hands of the Klingon-Cardassian Alliance. The Klingon-Cardassian Alliance ruled over the Alpha Quadrant in the 24th century, enslaving the Terrans and Vulcans across the galaxy. The alliance was overseen by a Regent, who by the time of 2372, was the Mirror Universe version of Worf.
Under Regent Worf were various Intendants who oversaw operations in various sectors of the Alliance’s territory. The most notable of these was Intendant Kira (Nana Visitor), who presided over the Cardassian space station Terok Nor, until she lost it to Terran rebels working with Prime Universe Captain Benjamin Sisko (Avery Brooks). This loss enraged Regent Worf, who was determined to retake the station, but he was defeated by Prime Sisko and the Mirror Universe’s crew of the ISS Defiant. It was the first of some heavy losses for Regent Worf that appeared to turn the tide against the Klingon-Cardassian Alliance in Star Trek: Deep Space Nine.
Regent Worf later tried to secure the use of a cloaking device that he hoped would help him bring the Terran Rebellion back in line. In Star Trek: Deep Space Nine season 7, epsode 12, “The Emperor’s New Cloak”, Quark (Armin Shimerman) and Rom (Max Grodenchik) from the prime Star Trek timeline traveled to the Mirror Universe to swap a cloaking device for Prime Grand Nagus Zek (Wallace Shawn). However, Quark and Rom were double agents, working with the Terran Rebellion to use the cloaking device against Regent Worf.
Rom adapted the cloaking device so that it would disable Regent Worf’s powerful warship, leaving him a prime target for the Terran Rebellion. The rebels captured the Regent in this final Mirror Universe episode of Star Trek: Deep Space Nine, hinting that they could finally turn the tide against the Klingon-Cardassian Alliance. To date, Star Trek hasn’t returned to the Mirror Universe in the 24th century, so it’s still unclear if the capture of Regent Worf was the first step in establishing a brand new Terran Empire, or if it led to violent recriminations against the Rebellion.
All episodes of Star Trek: Deep Space Nine are available to stream on Paramount+.
