|Affiliation:|| Terran Rebellion,|
In the mirror universe, the ISS Defiant was a Defiant class warship constructed by the Terran Rebellion, and was based on Defiant-class specifications stolen from Deep Space 9 in 2371. Once operational, the Defiant helped turn the tide in the war against the Klingon-Cardassian Alliance, especially at the Battle of Terok Nor, and represented a major boost to the rebels' morale.
The specifications for the Defiant were stolen by Miles O'Brien during a visit to the primary universe. "Smiley" O'Brien was able to download the schematics from Deep Space 9's computers and brought them back to the mirror universe, where construction began at Terok Nor, now under rebel control. While construction proceeded well with materials stolen from the Alliance, the powerful warp core on the Defiant caused the ship to almost shake itself apart during test flights, much like had occurred with the counterpart version.
With an Alliance fleet on its way to retake the station, O'Brien enlisted the help of Professor Jennifer Sisko to bring Captain Benjamin Sisko into the mirror universe, so that he could solve the problems on the Defiant.
Sisko was able to iron out the problems and even commanded the Defiant in the fight against Regent Worf's fleet.
In mid-2375, the Defiant was used to pursue Ezri Tigan and Brunt and to repel a further attack by the Alliance. The Defiant, under the command of "Smiley", came after them, hoping to reach the ship before the cloaking device was fully installed. Rom, however, manage to install the device, and the battle cruiser was able to track the Defiant undetected. After testing the cloak against the Defiant's sensors, the Regent ordered the ship to decloak and attack. During the battle that followed, the Regent's ship was disabled, due to sabotage Rom had inflicted during the installation of the cloaking device, and the Defiant was able to force a surrender and take the Regent prisoner.
A few months later, Rebellion Generals Zek and Julian Bashir gained the resources to build twenty-four more Defiant-class warships at their new shipyard at Empok Nor. Twelve of these were made, including the Capital Gain, Jadzia and Terra Victor. However, eleven were destroyed in the explosion that destroyed Empok Nor, and the Capital Gain was disabled.
The remaining twelve warships were built some time later by O'Brien as part of his plan for a Alpha Quadrant-wide "revolution" against the Alliance. That made a total of thirteen Defiant class warships including the Defiant herself.
Aside from the lack of a cloaking device and different internal furnishing, the ISS Defiant was virtually identical to her prime universe counterpart, proving herself one of the most powerful warships in the sector. The ship had four decks and was of a compact design. The bridge, located on deck one, incorporated the tactical, science and operations consoles on each side with one central helm console in front of the commander's chair.
The ship was equipped with four phaser cannons, two on both the port and starboard sides, at least one aft phaser emitter and a compliment of quantum torpedoes, the latter a previously unknown technology. Together with powerful deflector shields, the Defiant was able to hold its own against several smaller Klingon Birds-of-Prey and inflict heavy damage on the larger Galor-class and Negh'Var-class battle cruisers.
- Battle of Terok Nor