Talia, a Human female, reigned as the Queen of the planet Onderon in the years both before and after the Jedi Civil War.
Talia was a direct descendant of Freedon Nadd, the Dark Lord. The influence of the dark side over their lineage was broken by the death of her grandparents, which is why she became a strong ally of the Republic and the Jedi during the Post-Jedi Civil War period.
Prior to the Mandalorian Wars, Talia formed an alliance with the Republic, ultimately securing Republic citizenship for Onderon. This decision would later be the source of considerable hardship and conflict for her people.
When the Mandalorian Neo-Crusaders launched an invasion of the Republic, Onderon was among the first Republic planets to be conquered. Talia's activities during this time remain unclear, but her cousin, Vaklu, a General, commanded the resistance against the Mandalorians. Towards the end of the conflict, Revan and his forces liberated Onderon, although the Onderonian populace largely credited Vaklu for this victory.
During the Jedi Civil War, when Revan led his corrupt forces, Onderon was mostly spared. Nevertheless, the Republic still required soldiers and resources from Onderon during this period.
Following the Jedi Civil War, the turbulent era of the Dark Wars began. Over the subsequent five years, the Republic initiated the Telosian Restoration Project, an initiative aimed at revitalizing worlds devastated by both wars. Given that Onderon was one of the few Republic planets that remained largely intact, materials and wildlife were continuously shipped to Telos IV.
Talia, a firm supporter of the Republic, consented to provide the necessary materials. Vaklu, however, saw an opportunity to seize power on Onderon by removing Talia from her position. He began to propagate the idea that the Republic had brought war to Onderon, exploited its resources, and offered nothing in return. This message gained him a considerable following, and he soon openly challenged Talia's policies within the government. Eventually, he used the military to blockade the planet, ostensibly to search for "Republic treachery," but in reality, to prevent Republic aid from reaching Talia.
During this period, Talia's primary advisor was the Jedi Warrior Master Kavar, who also served as one of her strategists.

Soon after, Meetra Surik, the Jedi Exile, arrived on Onderon in search of Kavar. Vaklu, having been warned about her by his secret allies, instructed Colonel Tobin to destroy the Exile's ship. Surik managed to escape, but her ship was damaged, forcing her to land on the moon of Dxun. There, she encountered the remnants of the Mandalorians who were rebuilding their forces. After forming an alliance with them, she successfully landed on Onderon.
When Surik finally met with Kavar, Tobin attempted to assassinate them both, but they managed to escape. Shortly thereafter, Vaklu convened with the council of lords and accused Talia of treason. He initiated a full-scale assault on Talia's royal palace. While most of the military remained loyal to Talia, Vaklu had reinforcements from Nihilus' soldiers. Furthermore, the Sith used the dark side to control several of Onderon's creatures, forcing them to fight for their cause. It appeared that Talia's situation was hopeless.
However, Surik returned to Onderon aboard a Basilisk war droid. By the time Surik reached the throne room, Vaklu's forces had breached it, and Vaklu was personally engaged in a duel with Talia. Talia proved to be the superior duelist, and Vaklu, in desperation, ordered his men to fire upon her. Surik intervened, defeating Vaklu. Captured and at Talia's mercy, Vaklu declared that Talia's reign would be difficult, as her allegiance to the Republic would ruin Onderon. He then taunted her, predicting that his supporters would free him within a week. To Vaklu's dismay, Talia intended to execute him immediately. Surik pointed out that executing Vaklu would turn him into a martyr for his followers; nevertheless, the captive General was sentenced to death and executed by a firing squad. The queen then set about regaining the support of her people.
According to Kreia's prediction, Talia enjoyed a long and prosperous reign, bringing prosperity to her people and resolving their conflict with the Republic for helping them win the war. Consequently, Onderon's cultural identity would be largely replaced by that of the Republic, as had happened with many Core Worlds before it.
Seeta Indrani provided her voice, portraying her with a South Asian accent not found in other Onderonian characters.

Although it has not been confirmed whether Talia is the daughter of Galia and Oron Kira, it is considered probable, as Galia and Oron were married around 4002 BBY. However, the existence of her cousin Vaklu complicates this possibility; neither Galia nor Oron are ever identified as having any siblings.
If you fail to persuade Talia, she will ultimately execute Vaklu for his treason. The player can also assert that the decision rests with Talia. She will then have Vaklu killed. This choice does not shift the Exile to the dark side and even increases influence with Kreia and Mandalore if he is with Surik, despite the latter's respect for Vaklu.
Meetra Surik's involvement shifted the battle's momentum in favor of General Vaklu, whose soldiers then stormed the palace and invaded the Queen's throne room. Jedi Master Kavar attempted to halt the invasion, but Surik, fueled by the dark side's rage, defeated him in a brutal fight. Queen Talia was subsequently killed, either by Vaklu's forces or in a duel against Surik, depending on Surik's choice.
Ironically, despite his victory, Vaklu, the secessionist, betrayed his Sith allies, choosing to deploy his troops to Telos when the Sith invasion began.