10 Best Mirror Universe Characters In Star Trek

In the 24th century, the Mirror Universe is quite different from its Prime counterpart in various ways, but the biggest differences hinge on Deep Space 9. The space station, Terok Nor, is run by the Klingon-Cardassian Alliance, which is "staffed" primarily by Terran slaves.

Miles O'Brien was working in the ore processing center as a slave under the classification "theta." This earned him some respect among his fellow slaves. His position also made him available to repair Benjamin Sisko's raider whenever he docked it at the station. It was Sisko who hated the name O'Brien, so he decided to nickname him "Smiley."

When Julian Bashir crossed over from the Prime Universe, he convinced Smiley to aid him in his escape. He did so on the condition that he go with him but ultimately opted to remain and join Sisko's crew. Eventually, Sisko was killed by the Alliance, which left Smiley the leader of the Terran Rebellion.

He later crossed over to the Prime Universe to steal the plans for the USS Defiant, which made it possible for the Terran Rebellion to take control of Terok Nor. He remained the leader in command of the space station, and later, he negotiated the surrender of Regent Worf.