In 2382 Admiral Taris is appointed by Fleet Commander Tomalak as his second-in-command. She is ordered to mobilize and re-organize Romulus’ military forces.
When Tomalak suffers a defeat against Empress Donatra's fleet at Xanitla on Stardate 60900.31, Admiral Taris defects with twelve ships to the Imperial Romulan State. (2383)
The Empress sends Taris as representative to negotiations with the Romulan Star Empire at the Romulan capital, Ki Baratan, in 2384. Donatra recalls her when Praetor Tal'aura is found murdered. Taris is ordered to prepare for defending the Imperial territory.
In the following two years, Taris maintains a low profile during the troubles between the two Romulan states and passes many her responsibilities over to General Tebok. Late in the year, the Admiral informs Donatra about her investigation concerning claims that the Sword of the Raptor Star has been recovered at Levaeri V. She remains there until 2387.
That year, Taris ignores Donatra's order to return to Romulus and does not change course. In addition, she has Commander Arranhu send explosives into the Hobus star, causing it to go supernova and annihilate Romulus and Remus.
Following the destruction of the Romulan homeworld in 2388, Admiral Taris recalls all remaining vessels to return to Romulan space.
Over the next two years, she organizes these ships into a new fleet. She closes holes in the chain of command by approaching each ship's captain personally. Outside observers expect the Romulan military to be fully operational within seven months. Despite Taris' orders for the fleet to focus on relief efforts and the defense of border regions, Federation analysts warn that these ships could conquer civilian-led colony worlds to be brought under military control.
In 2391 Starfleet Command pulls back from the Klingon-Romulan border. Admiral Taris silences complaining colony leaders with a sharp rebuke: "We are Romulan. We fight our own battles. I would rather see Romulans die with pride in their hearts and swords in their hands instead of mewing for protection like scared younglings."
Later that year, a Klingon Councilor, J'mpok, commands a fleet of loyal houses to invaded the Zeta Pictoris System. His forces are defeated by a Romulan fleet led by Admiral Taris.
Following her decisive victory, Rator III proclaims her leader of the Star Empire. Achenar Prime and a dozen others worlds chime in. In response to that, Taris broadcasts in an empire-wide address: "I am a military commander, and I would prefer to remain so. The seas of politics are rife with submerged hazards and hidden perils, and a wise person does well to avoid them. But my Empire calls and I cannot resist her plea." She calls for the colony leaders to meet at Rator III for select representatives for a new Romulan Senate, make plans for organizing a government and building a new capital.
In 2392 the Romulan Colonial Organizational Committee, formed under Taris' directions, meets in the first completed building in Rihan, the new capital. Taris indicates her support for reviving the monarchy but notes that the Romulan people should have to decide whom to crown ruler.
Several ongoing RCOC legislative sessions are interrupted by Admiral Taris and General Tebok, who argue about the role of the Romulan military. While the General wants to protect the core worlds by abandoning areas bordering Klingon space, Taris regards it as their duty to protect every world. No decision is found in the debate. (2393)
When a permanent government is formed in 2394, Taris is made Praetor of the Romulan Star Empire.
Praetor Taris lodges an immediate complaint with the Federation Council when Captain Barax Wenn of the U.S.S. April reveals that the destroyed Starfleet ship U.S.S. Kelso was illegally using a cloaking device. (2395)
In 2396 the planet Kevratas is plagued by disease, making the Praetor quarantine Kevratas System by blockading it with Romulan ships, although a cure is available. Starfleet Admiral Zelle comments that Taris would be more compassionate if she saw someone dying from Bloodfire.
Taris orders General Tebok to take down the resulting Kevratan insurrection. Instead, he refuses to fire on civilians and the Praetor orders him to resign his position as Fleet Commander. The Romulan Senate overrules her decision and Tebok remains in command of the military. (2397)
In the following year, Tebok promotes General Velal, who is openly critical of the Praetor and her policies.
Tebok dies in 2399 when his ship, the I.R.W. Alth'lndor is destroyed by an antimatter containment failure. Praetor Taris orders that all fleets have to report to her directly until a new Fleet Commander is chosen. Velal objects to that and the Senate promptly passes a bill that calls for Senate approval for all high-level military appointments.
The Senate seeks to restrict the praetor's power even more in 2400, causing a clash between them and Taris. In a rare personal appearance, she argues: "In the absence of a monarch, and at a time of extreme upheaval in the Alpha and Beta quadrants we must have one voice to speak for our empire to the galaxy. Only by expanding the praetor's powers will we have stability and strength. A disharmonious chorus leads to chaos." Although Taris sways some Senators to her side, her general unpopularity with the Romulan populace makes the Senate proceed with the plan to limit the praetor's executive power.
As another possible problem for Taris, Starfleet Intelligence decode messages which make the reports about the Alth'lndor's destruction questionable.
In 2401, General Velal enters and alliance with the exiled Sela in order to remove Taris from power.
The conflict further fractures the empire and Taris faces a growing rebellion when Kevratas and Abraxas Prime support Velal. According to Starfleet Intelligence reports, Taris is locked in her rooms for a few days when the Romulan Second Fleet approaches Rator III on Stardate 80957.96, however, when Velal's fleet enters orbit, she is already gone. The reign of Taris is over when the Senate proclaims Sela Praetor. (2403)
In 2407, Praetor Sela revives Taris' idea about a Romulan monarchy. Later on, she becomes Empress of the Star Empire.
Taris and her Reman allies, including Commanders Arranhu and S'hanclado, hide with her in the Iconia System until they are found by Starfleet. Taris is captured and her responsibility for the Hobus supernova is revealed. (2409). She was held at Facility 4028 but disappeared, with the only hint being an Iconian energy signature detected near her cell.