Trey

"Trey", a moniker drawn from the sixth syllable of her birth name Romanadvoratrelundar, was the name most often used by a possible third incarnation of Romana who, in the form of a Matrix projection, led Gallifrey through its darkest hour. (AUDIO: Luna Romana) Romana II's projected regeneration into this incarnation was ultimately averted by Irving Braxiatel, (AUDIO: Enemy Lines) and other accounts depicted a different Romana III, although with some notable commonalities. (PROSE: The Shadows of Avalon, etc.)

A day to come
After Romana II returned from the Axis, she was aided by a Matrix projection of Romana III. This projection called herself "Trey" to distinguish herself from her predecessor.

Trey stopped Leela and Narvin from returning properly by trapping them in a Chronic Hysteresis. She then showed her younger self the results of the Pandora devastation. By offering her Capitol to her previous incarnation, Trey saved her thousands of years in rebuilding the planet. She had Romana exiled for the death of Kolspen of Unvoss. This occurred in the Matrix. (AUDIO: Renaissance)

When Romana disappeared, she went with Narvin and Leela to the Archives, where they met Tallan. She helped Narvin and Leela escape the Matrix before it collapsed. Trey later aided her second incarnation, after she left the Matrix, to defeat the Daleks, who were invading Gallifrey from the Matrix. She created a plan to have the Daleks return to the Matrix and trap them there, thus stopping them from invading Gallifrey itself. After their return, she stopped the invasion force from leaving the Matrix by closing its doors from the inside. (AUDIO: Ascension)

This Matrix projection of Romana III claimed to be the last of her people. (AUDIO: Renaissance)

Gallifrey's darkest hour
During her final term in office, Romana III had to deal with an anomaly near Earth, created using the Hand of Omega. A secret society, known as the Adherents of Ohm, were trying to gain power on Gallifrey, and she suspected that Narvin might be part of it. There was an attempt to assassinate her though Tauras managed to save her. She travelled through a black hole after Narvin tracked Ace there and found out that Tauras had set Omega free from the anti-matter universe. She tried to travel back into her own universe again but was stuck in the black hole as the type 160 TARDIS she was using ran out of power. She accepted that she along with Narvin and Ace wouldn't see Gallifrey again, until Irving Braxiatel saved her and went after Omega. (AUDIO: Intervention Earth)

After Omega returned, a war devastated Gallifrey. (AUDIO: Enemy Lines) As Gallifrey faced its "darkest hour", Romana began to clear sections of the planet in order to make room to build Battle TARDISes. She personally attended the decommissioning of Quadrigger Stoyn's workstation. (AUDIO: Luna Romana)

Rewriting of the timeline
Irving Braxiatel went back in time and stopped Romana II from regenerating, saying that Romana III had sent him to change her past to avert the conflict that devastated Gallifrey. Romana II then stepped down from the Presidency to ensure that that future would not take hold. In the wake of Braxiatel's intervention, Romana II was uncertain whether she would eventually regenerate into the same third incarnation or not. (AUDIO: Enemy Lines)

When Romana decided to run again for the Presidency during the first months of the Last Great Time War, she promised to promptly regenerate if she received the public vote, as she was barred by law from serving another term in that incarnation. However, she was instead defeated by Valerian. (AUDIO: Desperate Measures)

Personality
As a projection, she appeared to have a sunny and perky disposition, and was prone to wanting to give people hugs. (AUDIO: Renaissance) Despite this, she could be manipulative and ruthless, justifying her actions as doing the best for her people, and acting as a servant of history. (AUDIO: Renaissance, Intervention Earth) She was wistful about her first incarnation's naivety. (AUDIO: Luna Romana)

Behind the scenes

 * James Goss created Juliet Landau's "Trey" incarnation of Romana for the Big Finish audio stories. It was unclear which incarnation of Romana she was, and Goss initially contrasted her with "other future Romanadvoratrelundars" such as the "brilliantly glacial flapper", Romana III, who first appeared in Paul Cornell's The Shadows of Avalon. (VOR 56) However, Lady Trey was later definitively shown to be the third Romana in Enemy Lines.
 * Romana is the second Time Lord, after as played by Eric Roberts, to be portrayed by an American actor. Unlike Roberts, however, Juliet Landau plays her role with an English accent.