Mandana was a female Romulan in the 24th century. She was the wife of the miner Nero and was thought to have died on Romulus when it was destroyed by the Hobus supernova in 2387. The death of Mandana and her unborn child was a major contributing factor to Nero's subsequent campaign of vengeance against Federation and allied targets. (ST - Countdown comics: "Number One", "Number Three")
In 2387, Mandana was heavily pregnant with her and Nero's son. When Nero returned home to Romulus after witnessing unusual and energetic activity in the Hobus system she found him troubled; he was concerned the Romulan Senate had made the wrong decision in choosing not to act upon the advice of Ambassador Spock and work with the Vulcans the ensure the Hobas star could not cause a dangerous supernova which could threaten Romulus. After talking with Mandana, Nero concluded he must act against the will of the Senate, to help Spock with his plan. (ST - Countdown comic: "Number One")
Nero and his crew left with Spock aboard the Narada shortly after. Before leaving he tried to talk to Mandana into joining them, fearing that if they were not successful in time she would be in danger. Mandana however insisted Nero would be successful, and furthermore that she would not give birth to their son in a freezing mining ship. Promising to return as soon as possible, and before the birth, Nero left. (ST - Countdown comics: "Number One", "Number Two")
Unfortunately Nero and Spock were not successful; as Nero made the return journey to Romulus he watched in horror as the Hobus supernova blasted through Romulus, killing Mandana and their child. (ST - Countdown comic: "Number Two")
The destruction of Romulus, and in particular the loss of Mandana and their son, had a dramatic effect on Nero. He blamed Spock, the Vulcans, and by extension the Federation and its allies for not acting in time, and set about avenging his wife; targeting Federation and Klingon forces. Nero's quest for vengeance finally took him into confrontation with Spock, who had, too late for Romulus, been able to make a black hole to stop the Hobus supernova doing any more damage. Nero and Spock were both pulled into the black hole, and found themselves taken back in time, to the 23rd century of the Kelvin timeline. (ST comic: "Countdown, Number Four";TOS movie: Star Trek)
Upon arriving Nero contemplated his new predicament, he had travelled back in time, Romulus lived again, he could live to see Mandana born again! But no, his Romulus was gone, and he would have his revenge. Before he could do so however he found himself taken into captivity by the Klingons of that era. While in captivity he was able to obtain drugs which allowed him to relax, and dream of his life with Mandana. (TOS comics: "Nero, Number One", "Nero, Number Two")
Once Nero escaped the Klingons he continued his attacks, successfully destroying Vulcan. While attacking Vulcan he took Captain Christopher Pike captive, and while attempting to extract information from Pike to assist in his next attack, on Earth, he showed the captain a hologram of Mandana, explaining the source of his anguish. (TOS movie: Star Trek)
The name Mandana or Mandane means "eternal" in Persian and was also the name of Cyrus the Great's mother.