Shasa was a Selkath female who possessed Force-sensitivity. She existed during the time of the Jedi Civil War, a conflict that began due to the actions of Darth Revan, the Dark Lord of the Sith, and his Sith apprentice, Darth Malak. In 3956 BBY, Shasa and other young Selkath were enticed to enter the Sith Empire's Embassy located on Manaan, their homeworld, by an Iridonian mercenary. After joining the Sith, Shasa, along with her companions, underwent brainwashing through the use of mind tricks. Under the guidance of the Dark Jedi Master present at the Embassy, the Selkath learned the principles of the dark side.
During his raid on the Sith Embassy, Shasa encountered Revan, the former Sith Lord who had been captured and subsequently retrained by the Jedi Order. Revan, acting on behalf of Shaelas, Shasa's father, infiltrated the Embassy and attempted to persuade Shasa and the other Selkath to leave. However, they were hesitant to believe the amnesiac Jedi without proof. After Revan demonstrated to Shasa and her friends that the Sith were corrupting them solely to acquire kolto, Manaan's healing substance, Shasa and the Selkath renounced the dark side and departed from the Embassy. Following Malak's demise at the hands of a redeemed Revan in the final battle of the Jedi Civil War, Shasa established an order of Force adepts that persisted for nearly four millennia.

Shasa, a Selkath female with Force-sensitivity, was born to Shaelas on the homeworld of the Selkath, Manaan. In her youth, Shasa formed a friendship with another Selkath named Galas, who presented her with a token as a gift. In 3956 BBY, during the Jedi Civil War, which pitted the Galactic Republic against the Sith Empire led by the Dark Lord of the Sith Darth Malak, the Sith employed an Iridonian mercenary to entice young individuals from Manaan into the Sith Embassy. Shasa and Galas were among those who were lured.
Shasa, Galas, and several other young individuals joined the Sith and began to learn the ways of the dark side of the Force under the tutelage of the Dark Jedi Master at the Embassy. The Sith's objective was to corrupt and brainwash the Selkath youth in order to establish a puppet government on Manaan, enabling them to exploit the planet's exclusive resource: kolto, a highly valuable healing agent. The Sith informed Shasa and her companions that they were free to leave the Embassy if they desired. However, when Galas expressed his desire to leave, the Sith subjected him to torture that nearly resulted in his death. They then deceived Shasa into believing that Galas had been allowed to leave freely.

During his raid on the Sith Embassy, Shasa encountered Revan, the Jedi Padawan who had been retrained and was formerly the Dark Lord responsible for initiating the Jedi Civil War. Revan's infiltration of the Embassy was motivated by the requests of both Shaelas, Shasa's father who was searching for her, and Roland Wann, the Republic ambassador stationed there. Upon discovering the reasons for Shasa and her friends' presence in the facility, Revan attempted to persuade the misguided Selkath to abandon the Sith. However, Shasa's brainwashing by the Sith had made her unwilling to believe anything negative about them. Even when one of her fellow apprentices mentioned the destruction of Taris, Shasa dismissed it as a fabrication by the Republic. Revan convinced Shasa and her friends to grant him the opportunity to find concrete evidence of the Sith's treachery. While searching the Embassy, Revan located Galas, who entrusted the Jedi with the token he had given to Shasa during their childhood. Before his death, Galas implored Revan to inform Shasa that the Sith were evil. Revan presented the token to Shasa, who initially refused to believe that the Sith had killed Galas. After Revan successfully convinced her to accept the truth, Shasa and her friends promptly left the Embassy and abandoned their dark side training.
Following Darth Malak's death at the hands of Revan and the defeat of the Sith Empire, Shasa and several other Selkath participated in a battle against the Sith forces in Ahto City, ultimately defeating them. Shasa came to the realization that if Manaan was to maintain its neutrality, the Selkath could not rely on either the Jedi Order or the Sith. Nevertheless, Shasa believed that Force-sensitive Selkath required proper training to effectively utilize their abilities and avoid succumbing to the dark side. Shasa and the other Selkath who had received training from the Sith established a doctrine centered on peace and defense, leading to the creation of an organization initially known as the "Order." This group soon became recognized as the "Order of Shasa." Shasa's order of Force adepts endured beyond her lifetime, persisting for nearly four millennia, until the time of the Galactic Civil War.
Having undergone brainwashing by the Sith, Shasa and the other young Selkath embraced everything the Sith conveyed. She rejected any negative information regarding the Sith and was convinced that they were victims of Republic lies and half-truths. Upon discovering that the Sith had tortured and murdered her childhood friend Galas, Shasa initially hesitated to accept this revelation. However, she eventually acknowledged the truth and apologized to Revan for her initial doubt. After establishing her order of Force-sensitives following the conclusion of the Jedi Civil War, Shasa remained cautious about seeking assistance from the Jedi or any other Force-using organization. If darksiders began to gain influence within her order's ranks or exert control over new members, Shasa would seek guidance from a Jedi whom she trusted. Alternatively, Shasa would seek counsel from a Force-based tradition with a reputation she deemed positive, such as the Jal Shey.
Shasa possessed bilingual proficiency, enabling her to speak and understand both Basic and the Selkath.
During her confrontation with Revan in the Sith Embassy, Shasa wielded a Mandalorian heavy blaster and a Sith energy shield in combat. She also possessed a cybernetic implant known as the Bavakar cardio package. Following the Jedi Civil War, Shasa owned a Fira sword, a datapad, and a comlink. As a Selkath, she had the ability to breathe both underwater and on land.

Given her inherent connection to the Force, Shasa was able to manipulate objects using telekinesis. She also employed the Force to execute mind tricks and could generate a swirling vortex of Force energy to encircle her adversaries. After establishing her order of Force adepts, Shasa developed additional Force powers, including a technique that allowed her to detect deception through the Force. She also devised two other techniques: one involved using the Force to sense the call of a massive Firaxan shark known as the Progenitor, whom the Selkath revered as their evolutionary ancestor, and command it against her enemies. The other was a telepathic power that simulated wave action reminiscent of Manaan's oceans. Shasa was adept at fighting both unarmed, with a blaster, and with a fira.
Shasa made her debut in the 2003 video game Star Wars: Knights of the Old Republic, created by BioWare. Her narrative was further expanded upon by Cory J. Herndon in the third installment of the Planet Hoppers article series, Manaan: Depths of History, published by Wizards of the Coast in February 2004. Shasa was also mentioned in the Knights of the Old Republic Campaign Guide, released on August 19, 2008, and served as the central focus of the seventh web enhancement for the campaign guide. Abel G. Peña, a writer for the Knights of the Old Republic Campaign Guide, was questioned on his official thread on StarWars.com regarding an image from the campaign guide depicting a Selkath engaged in combat with a Sith trooper. Peña confirmed that the Selkath in the image was indeed Shasa.
Within the game, there exist two methods to persuade Shasa and her Selkath companions to abandon the Sith. The first involves a datapad located in the chambers of the Dark Jedi Master. Upon showing Shasa the datapad, she and her friends immediately leave the Embassy to alert the local authorities. The second method involves a token given to Revan by Shasa's dying friend Galas. However, Shasa initially becomes reluctant, even accusing Revan of Galas' murder. If the player possesses sufficient persuasion skills or has Bastila Shan, the Jedi Knight, in their party, Shasa and her Selkath companions will accept the truth. In the non-canon dark-sided storyline, Revan can either eliminate Shasa and her friends or commend them for embracing the Sith ways, allowing them to continue under the Sith's guidance. Should the player fail to acquire the quest to locate Shasa before entering the Sith Embassy, they will be unable to obtain information to reason with the Council in Ahto City, potentially leading to Revan's execution upon exiting the Sith Embassy.