Silvain Barash, a Kage female Jedi Master, proclaimed herself to be the sibling of the Ikkrukkian Jedi, Porter Engle. She joined her brother in his adventures as a Jedi gunslinger around 382 BBY. Following a serious error during a mission on Gansevor, Silvain pledged to withdraw from active Jedi Order duties while still remaining a Jedi. This allowed Engle to refocus her efforts on connecting with, and understanding, the Force. Her practice became known as the Barash Vow, named in her honor.
Silvain Barash was a Kage female born on the planet of Quarzite. At some point, she became a member of the Jedi Order. Around 407 BBY, when Silvain was a Jedi youngling at the Jedi Temple located on Coruscant, she and other younglings were introduced to training lightsabers. She initially avoided forming friendships, believing she didn't need them. However, on that very day, she encountered Porter Engle, who persuaded her to consider him as a friend. Consequently, they cultivated a profound connection, eventually regarding each other as siblings. They functioned in harmony, complementing each other's strengths and weaknesses. Silvain possessed exceptional talent in discerning the intentions of others, while Engle excelled as a renowned lightsaber duelist.

Around 399 BBY, the Jedi Masters at the temple grew concerned about their growing attachment and separated them as a result. However, the pair vowed to intentionally perform worse while separated, believing it was only reasonable that they work together. This strategy proved successful, and they were reunited around 397 BBY at the Jedi Temple. Upon their reunion, the Kage revealed to Engle that she had been admitted to the Jedi Order at a slightly older age than usual. She also explained that her species' memories began almost from birth, meaning she could still recall her family. Although she did not regret being separated from her family, she felt a sense of loss, prompting her to ask Engle to be her brother. From that moment forward, they addressed each other as brother and sister.
By 382 BBY, both Silvain and Engle had become Jedi Knights and were stationed at the Office of the Frontier, where they effectively utilized their combined skills. One mission took them to the Boneworld, a distant planet famous for its abundant supply of ambercryst. Before their departure, Engle became entangled in a dispute between two prospectors, Dregg and Ralen, who were arguing over a satchel filled with ambercryst. While Engle listened to both sides, Silvain used her abilities to determine that Ralen was being truthful. Acting on her sister's guidance, Engle ruled in favor of Ralen and repelled Dregg's subsequent attack, forcing him to flee. With the matter resolved, Silvain and Engle boarded a shuttle and returned to the Office of the Frontier to select their next assignment. Out of 201 active petitions, Silvain chose the one that felt most correct based on her intuition – a plea from the city-state of Firevale on Gansevor, which was under siege. Silvain was convinced that the Force was guiding them there, a belief strengthened by the unexpected arrival of Helion Volte and their Pathfinder team, who were also scheduled to travel to the Tammuz sector and offered them transportation to Gansevor. Before dropping them off, Volte's pilot, Sallee Ooph, offered them an EX droid to facilitate communication with the wider galaxy. Silvain confidently asserted that she and her brother could easily handle the situation on Gansevor and that Volte's team should keep the droid, as they were venturing into more uncharted territories.
Upon arriving at Horatio, the planetary capital of Gansevor, Silvain and Engle were greeted by Seleen, Firevale's envoy who had requested their assistance. Seleen explained that Firevale, known for controlling the planet's supply of baudraxite, had been unexpectedly besieged by the rival city-state of Bethune. Given that the central government in Horatio lacked military authority, Firevale needed the Jedi's help to provide supplies for its starving citizens and break the siege. Silvain and Engle cautiously agreed to escort a supply convoy to Firevale, but cautioned Seleen that they would need to investigate both sides to determine how best to resolve the conflict. Together, Silvain and Engle positioned themselves atop one of the transports in the convoy, with Silvain confidently stating that they could send the Bethunians home without firing a shot. However, her confidence proved misplaced as the besieging army's guns opened fire on the incoming ships. Silvain and Engle managed to divert the missiles into nearby mountains before ordering the convoy to retreat and land out of range. They approached the Bethunian forces on foot, but were again immediately fired upon. Silvain was struck in the forearm during the attack, which only ceased when Engle disarmed a group of soldiers and demanded to speak to their leader. Impressed by Engle's lightsaber skills, the Bethunians allowed the Jedi to pass and meet with Field Marshal Tozen, who expressed his displeasure at the Jedi's interference and informed them that the siege was due to Firevale's kidnapping of Bethune's princess, Sicatra. Silvain told Tozen that they were not there to take sides, but to ensure justice for both Firevale and Bethune, and that they needed to investigate both sides further. She persuaded Tozen to allow the convoy to pass through the siege while she and Engle spoke with the Firevale royal family. However, unbeknownst to Silvain, Tozen contacted the mercenary general Abediah Viess, who had been hired by Bethune to support the siege, and asked her to bring her forces to help secure victory. In Firevale, Silvain and Engle were greeted by Magistrate Renata and Prince Colden, who were surprised that Seleen had managed to arrange assistance for their struggling city. Colden informed the Jedi that Sicatra, the Princess of Bethune, was actually his wife and had sought asylum in Firevale.
Before further discussions could take place, Firevale's alarms announced the arrival of Viess and her mercenaries above the besieging army. The threat of Firevale's anti-air defenses prevented Viess from launching an aerial bombardment, but the number of mercenary and Bethunian soldiers and guns threatened to quickly overwhelm the city gates. As the guns resumed firing, Silvain sent Engle to distract the attackers and buy time while she investigated the situation further. Engle managed to persuade Tozen to briefly halt the barrage by promising that Silvain would locate Princess Sicatra. Meanwhile, in Firevale's palace, Silvain and Colden met with his mother, Queen Keraan. Keraan argued with her son, blaming his love affair for the siege, but they were interrupted by the arrival of Sicatra herself. Silvain took Sicatra aside to hear her side of the story. Sicatra claimed that she and Colden had decided to live in Firevale because the people of Bethune would never accept a king from Firevale, mainly due to Firevale's control over the baudraxite supply. Sicatra also claimed that she had fled so suddenly because she was pregnant and feared for her child's future, as it would be taken from her at birth and given to someone else to raise due to its Firevale blood. Completely believing Sicatra, Silvain contacted Engle and instructed him to persuade the Bethunians to end their siege and return home. However, at that moment, Tozen and Viess agreed to resume hostilities, with Tozen agreeing that Viess and her mercenaries would be allowed to plunder Firevale for twelve hours after it fell.
As Engle attempted to stop the besiegers and defeat Viess, the bombardment caused widespread destruction and death within Firevale's walls. Colden and Keraan argued about how to respond to the renewed onslaught, with Colden suggesting they open the gates and Keraan countering that such an action would force her to abdicate. Silvain argued that Engle would prevail and force the mercenaries to retreat, but unbeknownst to her, Viess betrayed Tozen and had him shot for his reluctance to intensify the bombardment and raze Firevale. As the rate of fire from the Bethunians and mercenaries increased, a mortally wounded Tozen contacted Sicatra and revealed what had happened, causing her distress. She then revealed the truth to Silvain, admitting that she and Colden had orchestrated the siege so that Colden could seize power from his mother and include Bethune in the baudraxite trade. Even Sicatra's pregnancy had been fabricated to gain Silvain's sympathy. These revelations prompted Keraan to attack her daughter-in-law, but Silvain used the Force to prevent the Queen from striking. Sicatra then addressed the Bethunian troops below the city walls, urging them to turn against the mercenaries who had betrayed Tozen and threatened to destroy their world. Sicatra's speech was successful, forcing Viess and her soldiers to flee the battlefield and ending the siege. However, a grieving Silvain informed the Princess that her actions had still led to mass death and destruction, and that Silvain herself also bore responsibility for what had occurred.
With the conflict resolved, but at a great cost, Silvain and Engle debriefed together. She told her brother about Colden and Sicatra's deception and how she had been fooled. Engle tried to comfort her and suggested they return to Horatio to be picked up by Helion Volte's pathfinder team, but Silvain decided to stay. She felt immense guilt for ordering Engle to engage the mercenaries, escalating the conflict, because she had believed Sicatra's story. Silvain told her brother that she needed to listen to the Force; she could not allow Engle or any other Jedi to trust her until she was certain that she was hearing the Force clearly again, and therefore she would take no further action on behalf of the Jedi Order. Silvain's personal commitment, which would later be known as the Barash Vow, was relayed to the Jedi High Council by Engle who, when asked where his sister had gone, claimed that he did not know.
In 228 BBY, approximately 171 years after Barash took her vow, General Viess claimed to know Silvain's location while the Mirialan was attempting to escape from Porter Engle.
Silvain Barash first appeared in the 2022 comics Star Wars: The High Republic — The Blade, written by Charles Soule for the Star Wars: The High Republic multimedia project. A concept illustration of her was revealed on October 14, 2022, before its publication in The Art of Star Wars: The High Republic (Phase One).