A Terran slave who worked in the ore processor on Terok Nor, O'Brien was given special privileges because of his skill repairing machinery. When Bashir and Kira were sent to the processing facility after an accident threw them into the mirror universe, O'Brien helped them to escape from the station and subsequently joined the crew of mirror Sisko's privateer vessel. [2] When mirror Sisko was killed in 2371 O'Brien kidnapped the real Sisko and forced him to take the place of his mirror so that he could meet with the mirror Jennifer Sisko and convince her to defect to the rebellion. [3] While kidnapping Sisko, O'Brien downloaded the designs of the USS Defiant from Deep Space Nine's computer system; the rebels used the plans to build a copy of the ship. When they captured Terok Nor they planned to use their Defiant to defend the station, but problems with the design meant that the ship was not combat ready. O'Brien recruited Sisko to assist in completing the ship and defending the station from an Alliance fleet. [4] When Regent Worf and Intendant Kira obtained a cloaking device from our universe, O'Brien managed to overcome the Regent's ship and capture him thanks to Rom's sabotage efforts. [5]
