In the mirror universe, the Terran Rebellion-Alliance war, also known as Terran Rebellion, was a conflict between the Terran Rebellion and the Klingon-Cardassian Alliance in the 2370s. Against overwhelming odds the rebellion, which came to be called the Terran Resistance Forces, scored several important victories against the Alliance and restored hope to the defeated slaves.
Benjamin Sisko starts the Terran Rebellion
They managed to raise a full-scale rebellion, gathering together a band of troops and ships based in the Badlands. Although Sisko was killed in 2371, trying to reach Terok Nor to convince his former wife, Jennifer Sisko, to join the Terran cause, the rebellion continued on, led by Miles "Smiley" O'Brien, with a little help from the "primary universe" universe version of Sisko. (DS9 episode: "Through the Looking Glass")
In 2372, the rebels scored their first major victory: the capture of Terok Nor from the Alliance. In order to maintain their power and defend their new conquest, the rebels built a new warship, a replica of the Starfleet warship USS Defiant, which they also named ISS Defiant. This powerful little ship was successful in defending the newly-captured station at the Battle of Terok Nor. (DS9 episode: "Shattered Mirror")
One of the many acts of internal sabotage of Alliance operations was to end their ability to use their cloaking devices by using new forms of sensors to disrupt the cloaking fields and the sensors detected the ships through the field. This crippled the Alliance's war machine to a massive degree.
The rebels, now calling themselves the Terran Resistance Forces, won a great victory in 2375, when the ISS Defiant, thanks to sabotage by the "primary" version of Rom, managed to capture Regent Worf, the leader of the Alliance. When last seen, the rebels' march towards total victory appeared to be well under way. (DS9 episode: "The Emperor's New Cloak")
The Rebellion experienced a massive boost in manpower when the entire Xenexian population (which numbered millions), under their new leader M'k'n'zy of Calhoun, joined the Rebellion against the Alliance. (NF - Mirror Universe novel: Cutting Ties)
Not long afterwards, 'Mac' and his ship, the Excalibur, rescued Selar, who had been undercover posing as a Romulan. She found evidence that the Romulans were building a thalaron radiation weapon for the Alliance. Mac, Selar, and Soleta arrived on Romulus in disguise as Romulan scientists, only to be discovered by Praetor Hiren. However, Alliance soldiers ambushed the four of them and discovered that the Alliance planned to destroy Romulus with the thalaron weapon. Unfortunately, although the four escaped death, the bomb went off, completely annihilating the Romulan homeworld. Despite this, Praetor Hiren decided to give command of the entire surviving Romulan fleet to Mac, so that they could join the Terran Rebellion's fight against the Alliance. (NF - Mirror Universe short story: "Homecoming")
Another major breakthrough was when the Rebellion's scientists successfully copied the designs of the counterpart universe Defiant-class warships and Romulan cloaking devices. These combined improved the Rebels' space warfare capabilities and cost the Alliance many ships and facilities.
The fighting began to spread and slaves everywhere deserted their posts and joined the Rebellion at Terok Nor or one of the Rebels bases in the Badlands . One such case was Keiko Ishikawa, who became Smiley's girlfriend and first officer. They later became the parents of Molly O'Brien.
Rebellion leaders Zek and Julian Bashir eventually stole vast amounts of resources and equipment from Alliance territory and planned to construct a fleet of cloaked Defiant-class warships at the abandoned Alliance space station Empok Nor and use them to destroy the Alliance homeworlds of Cardassia and Qo'noS. Unfortunately, these plans were undone when Empok Nor was destroyed and many rebel leaders were killed. O'Brien managed to rally his troops from the brink of despair by promising a "Revolution" against the Alliance (when in fact he had no idea how to do this). (DS9 - Mirror Universe novel: Saturn's Children)
The Bajoran dissident movement supported the Terran Rebellion. (DS9 novel: The Soul Key)
The final victory of the Rebellion eventually came in January 2379 and Earth signed an armistice with the Alliance. However, the newly freed Earth elected not to restore the Terran Empire. Humanity instead became a member of a new organization, the Galactic Commonwealth. (ST - Mirror Universe novel: Rise Like Lions)