Nason was a female Human from the planet Telos IV, and the youngest daughter of its governor, Crion. Her brother, Xanatos, was training as a Padawan within the Jedi Order. She held the status of a Telosian princess.
Circa 53 BBY, Lord Crion devised a scheme to crush the growing insurgency on Telos IV that posed a threat to his authority, a goal in which Nason's lover, Dairoki, played a supporting role. Dairoki manipulated events to establish a connection between the Telosian rebels and the nearby world of Toprawa, leveraging the Telosians' strong sense of nationalism. Crion believed that the notion of off-worlders collaborating with the insurgency would erode popular support for the rebels. To achieve this, Dairoki infiltrated the insurgency, concealing his allegiance to Lord Crion from almost everyone, including Nason, who acted as a liaison between her father and the fallen Jedi.
Their strategy commenced with the assassination of Liora, the High Priestess of the Order of Than-Onna, a respected peacemaker. Dairoki personally committed the murder, utilizing the Force to hurl her from a high platform. Crion intended to blame Toprawa for the assassination, reinforcing the idea that their neighbor sought to destabilize Telosian society.
In a frigid cavern located outside the city of Thani, Nason rendezvoused with Dairoki. He noticed her trembling and, although she attributed it to the cold, he sensed her fear and attempted to reassure her. He reminded her that she was the planet's heir, and their actions would secure her rise to power and unify the world under her rule. Nason acknowledged the reasoning, but expressed reservations about the methods.
The Jedi Order, alarmed by the escalating tensions in the Telos system and the murder of the pacifistic Liora, dispatched Jedi Master Qui-Gon Jinn and his Padawan Xanatos—Nason's brother—along with Master Tahl and an unassigned Padawan, Orykan Tamarik, to investigate and de-escalate the conflict. Xanatos grappled with conflicting emotions, but Jinn reminded him that this was merely a test. Upon arriving on Telos IV, their shuttle was immediately attacked and shot down above the Chodo Habat Parkway. The Jedi survived the crash by using the Force, only to be confronted by Telosian rebels. Just as a rebel was about to kill Xanatos, Crion and his guard intervened. With the battle concluded, Crion welcomed Xanatos back to his homeworld.
After receiving guidance from Hukowl An Devi, one of Crion's advisors, the Jedi proceeded to the capital. Meanwhile, Dairoki met with Nason, inquiring if she had seen her brother since his arrival. Despite Nason's disguise, Dairoki recognized her. He removed her veil to kiss her, but she rebuked him, and he instead emphasized their political machinations. He reminded her to exploit her relationship with her brother, though Nason doubted his susceptibility to such manipulation.
The Jedi continued their investigation into Liora's murder, visiting the temple where she was slain. Orykan experienced a brief vision of the murder, but the darkness of the event overwhelmed her, causing her to collapse. Jinn also sensed remnants of the event, concluding that a Jedi had been involved in Liora's death. Simultaneously, Master Tahl visited the city's library to gather information and encountered a man dressed as an Antarian Ranger who claimed that the attack on the Jedi was intended as a message. Tahl interrupted his conversation, prompting the "Ranger" and his two companions to attack her. She killed the two rebels, but the Ranger escaped, leaving the Jedi with unanswered questions. That night, Jinn shared with Tahl his experience at the temple, describing the attacker's presence as feeling like, "A Jedi. And yet, not a Jedi". Tahl then highlighted the historical connection between Antarian Rangers and Jedi training, and Yoda's rejection of Tahl's request to enlist their assistance in this mission; the two Jedi Masters concluded that a true Antarian Ranger might have murdered Liora.
Later that night, Nason again met with Dairoki in the frozen cavern outside the capital. She noted his absence from the ceremony commemorating Liora's death, but he explained that while he could move undetected, he could not risk being seen by the Jedi. The man Tahl had encountered was a false Ranger working for Dairoki, which made the scarred former Padawan even more cautious. Nason, sensing a shift in their relationship, was pleased that Tahl had failed to question the "Ranger".
The following day, Dairoki met with the false Ranger, who offered excuses for his near encounter with Tahl. Dairoki then presented the man with a lightsaber, assuring him that his actions would be remembered.
Meanwhile, Nason and Xanatos engaged in a hoverbike race across the Telosian desert, with Nason reminiscing about their shared past. As they paused briefly and then resumed racing, Dairoki observed them from a nearby outcrop, seemingly displeased that their bond was strengthening instead of her manipulating him as they'd intended. Nason and Xanatos returned to the capital, seeking their father. Tahl encountered them as the sounds of blaster fire erupted nearby. The insurgents had launched an attack against Lord Crion and a small contingent of his guards, encircling them near a fountain. Xanatos warned his sister to stay away as he, Tahl, and Jinn, who had just arrived, joined the battle. Dairoki, hidden in a dark alcove, seethed at the rebels' failure to follow his instructions. He entered the fray, attacking an insurgent, much to Crion's anger, while Jinn immediately recognized the former Jedi. Nason was cornered during the fight, and as Hukowl An Devi attempted to reach her, she was shot in the abdomen, resulting in her immediate death. Dairoki, consumed by rage, attacked both insurgents and Crion's guards. The remaining rebels fled, as did Dairoki, vowing to act "another day". Enraged by the loss of his daughter and Dairoki's betrayal, Crion fired at the fleeing man but missed. In the aftermath of the battle, Jinn and Tahl recognized Dairoki by his extensive scars, and Tahl suggested that their mission might be a test for Jinn.
Following Nason's death, both Crion and Dairoki became distraught, and their actions were driven by emotion. Dairoki infiltrated Lord Crion's bedchambers, bypassing numerous armed guards and awakening him. Crion berated him for his presence, but Dairoki reminded him that he was supposed to see Nason. Crion mocked him, and Dairoki asserted that his daughter was more than just a contact. Crion accused him of causing Nason's death, while Dairoki explained his attempts to stall the rebels. Dairoki apologized for failing to protect Nason, but stated that his planting of the lightsaber should solidify the Antarian connection to the insurgency, and therefore the rebels' connection to Toprawa. Crion dismissed Dairoki's ideas, arguing that if the Jedi had seen him, his manipulations would be ineffective. He ordered the failed Padawan to leave the planet immediately. When Dairoki protested, Crion struck him across the face and threatened him to leave his world. Dairoki silently slipped back into the night.
However, the manipulations of Nason and Dairoki did succeed, and the next morning Minister An Devi delivered a speech to a crowd of Telosians, outlining the alleged conspiracy between the insurgents, the Antarian Rangers, and the Toprawan government. Diplomatic relations with Toprawa were severed, native Telosians were repatriated, and Toprawans were deported from Telos IV. Evoking nationalist sentiments and the memories of Nason and High Priestess Liora, An Devi called for unity and strength. Later that day, Crion addressed hundreds of Telosian soldiers. He ordered the military to suppress all those who supported the insurgency, even if it meant waging war in their own streets. His son, Xanatos, had left Jinn and joined him, and Crion used his appearance to claim that the Jedi Council supported this action.
Soon after Crion's call to war and the ensuing violence swept through the capital, Dairoki entered Minister An Devi's apartment as the man watched another Ithorian sleeping. Dairoki assured the minister that they were on the same side, and An Devi acknowledged his assistance during the attack that killed Nason, as well as his visible grief. Dairoki expressed frustration with Crion's actions, fearing that the lord was losing focus as he mourned his daughter. The scarred man worried that after all their efforts to unify Telos IV, Crion would allow the violence to escalate and worsen the situation. He lamented that Nason and Liora's deaths would be in vain, inadvertently revealing that he and Crion were responsible for both. Appalled, An Devi attacked him, but Dairoki swiftly kicked out the Ithorian's leg, knocking him to the ground. As An Devi shouted after him, Dairoki fled the minister's apartment and declared his intention to leave the planet.
Dairoki's fears materialized after he fled Telos IV. Widespread violence resulted in countless deaths, while An Devi used the information revealed by Dairoki to enlist Jinn and Tamarik in quelling the chaos. An Devi revealed to all Telosians that there was no external conspiracy, and that Crion himself had betrayed them. Although Crion's guards remained loyal, An Devi's speech incited even more people to rise up against Crion's rule. Jinn pursued Crion, hoping to rescue Xanatos from his father's madness, but the lord attempted to duel Jinn instead. Using a sword against Jinn's lightsaber, the fight was brief, and Crion fell to his death among the decorative fires of his palace. Consumed by his father's machinations and the dark side of the Force, Xanatos betrayed the Jedi, attacking both Tamarik and Jinn, and disappeared amid the mob violence that engulfed the palace. With the truth behind Crion's conspiracy exposed and with Xanatos and Dairoki abandoning the cause of unifying Telos IV, the civil war ended, and the warring factions negotiated a cease-fire.