Born circa 3,979 BBY, Bastila Shan was the quintessential Jedi: trained from a young age and gifted with a natural ability in the Force that gave her both renown and considerable pride. Despite her youth, Bastila was skilled in the rare art of Battle Meditation -- through sheer force of will she could influence the course of a battle. Through this Force power, one side was given courage and strength while the other is sapped of their will. This ability alone put Bastila into the forefront of the Galactic Republic's plan to defeat the Sith.
Brash, impulsive, and overconfident, Bastila seemed to walk invincible through her world, though that was hardly the case. Bastila was well aware of the responsibility that pressed down on her shoulders. Her Jedi masters urged her to be cautious, but Bastila turned every fiber of her being towards defeating the Sith menace and proving herself to the Jedi.
Bastila possessed all the qualities that separate those special few destined to leave their mark on history, but her very youth and determination were always threatening to become that which eventually consumed her.
Shortly before Darth Malak's rise to power, Bastila wielded a single-bladed yellow lightsaber, the standard weapon of Jedi Sentinels at that time. However, by the end of the Second Sith War, Bastila had exchanged this sword for a double-bladed yellow lightsaber. Though seemingly a small thing, this change in Bastila's weapon of choice ultimately speaks greatly of her character. The double-bladed lightsaber was first invented by the great Dark Lord of the Sith Exar Kun. A difficult weapon to master, it has been wielded by extremely few over the millennia, and at no time in greater abundance than during the Jedi Civil War, when it became very popular in Darth Revan's new Sith Empire. The double-bladed lightsaber is a weapon used almost exclusively by followers of the dark side of the Force due to the fact that its second blade exists only to increase the weapon's deadliness. Among the Jedi, the weapon is favored only by those who tend to skirt along the edges of the dark side. Only one other Jedi is known to have wielded such a weapon during this era: Master Zez-Kai Ell. The fact that Bastila, a mere Padawan, chose to carry a double-bladed lightsaber speaks not only of her arrogance, but also of the fact that she walked much closer to the dark side than she ever believed.
Bastila was part of the strike force sent to capture Darth Revan, Dark Lord of the Sith, during the Jedi Civil War. Though she managed to corner Revan on the bridge of his flagship, it is likely that she and the other surviving members of the Jedi strike team would have been killed by the Dark Lord had Revan's apprentice, Darth Malak, not chosen that moment to betray his Master by opening fire on his ship. Though Revan's mind was damaged beyond repair in the attack, Bastila managed to save his life, thus forging a powerful Force bond between the two. Revan was brought to the Jedi Council, reprogrammed with a new identity as a Republic soldier, and sent to serve under Bastila on the ship Endar Spire.
Over the planet of Taris, the Endar Spire was ambushed by a Sith fleet intent on capturing Bastila, forcing the crew to abandon the ship and land on the planet surface. Among the few survivors were Bastila, Revan, and Republic officer Carth Onasi. While Revan and Carth were able to escape undetected, however, Bastila's lightsaber was lost in the crash, and she was quickly kidnapped by a swoop bike gang known as the Black Vulkars. The Vulkars believed her to simply be a Republic officer, and planned to award her as a slave to the winner of the annual Taris swoop race.
Meanwhile, Revan and Carth set up base in an abandoned apartment and learned of Bastila's enslavement. Hoping to rescue Bastila by winning the tournament, Revan volunteered to ride a dangerous experimental swoop. He emerged victorious, but Brejik, leader of the Black Vulkars, refused to surrender his beautiful young Jedi slave. It was at this moment that Bastila used the Force to free herself from her cage, and together she and Revan finished off Brejik and his gang. Stealing the ship Ebon Hawk from the crime lord Davik, Revan, Bastila, and Carth, along with Twi'lek slicer Mission Vao, her Wookiee partner Zaalbar, Mandalorian mercenary Canderous Ordo, and the astromech droid T3-M4, escaped the planet just as Malak destroyed the Taris city with an orbital bombardment in an attempt to end his long hunt for Bastila.
After making it off Taris, the group left for the Jedi Academy on Dantooine to seek guidance on training the memory-wiped Revan. After a remarkably fast training, the two were sent to investigate ruins on Dantooine which had been visited by the Sith Lords Revan and Malak. There they found a Star Map which told of the Star Forge, an ancient alien artifact of unknown significance. The map showed the planets Tatooine, Manaan, Kashyyyk, and Korriban as having other maps. In order to defeat the Sith, the Jedi enclave council sent Revan, Bastila, and their companions to find other Star Maps on these planets and piece together the location of the Star Forge.
As the group made their way to the fifth Star Map, the Ebon Hawk was captured by the Sith flagship Leviathan, and Bastila was kidnapped by the evil Admiral Saul Karath. Imprisoned along with the rest of the crew, Bastila was brutally tortured by the sadistic Republic traitor in order to coerce Revan into revealing their mission, though Karath already knew the answers to all of his questions. It wasn't long before Bastila, Revan, and Carth escaped, however, killing Admiral Karath and battling their way toward the Leviathan's docking bay. On their way to freedom, however, they were intercepted by Darth Malak who revealed Revan's true identity. Though Revan and Carth managed to escape, Bastila was kidnapped by the Dark Lord and held as his prisoner. After torturing her for weeks with Force lightning, drug injections, and other twisted means, Malak eventually succeeded in forcing Bastila to give in to her hate. She fell to the dark side and became the Dark Lord's apprentice, replacing the dimwitted Darth Bandon as Malak's double-bladed lightsaber-wielding pawn. Bastila, consumed with the treachery inherent in the way of the Sith, met with Revan atop an ancient Rakatan temple and tried to persuade him to reclaim his former title of Dark Lord of the Sith.
Alternate Universe Light Side Choice
After confronting Bastila again on the Star Forge, Revan defeated her in a light-saber duel. Bastila begged Revan to kill her. The player can choose either to kill or to spare her, in any case, Revan later confronted Darth Malak and killed him as well. With Bastila dead or supporting the Republic, the Sith fleet lost the advantage of Bastila's battle meditiation. The Republic destroyed the Star Forge after the Sith starships fell into disarray. Victorious, Admiral Dodonna awarded Revan and the surviving crewmen of the Ebon Hawk with the Cross of Glory, and Master Vandar honors Revan as a redeemed Jedi Knight.
Alternate Universe Dark Side Choice
Revan gave in to the dark side. He/she and Bastila killed Jolee Bindo and Juhani. When returning to the Ebon Hawk, Revan persuaded the rest of the team to join the dark side. The droids HK-47 and T3-M4 were already programmed to do so, and Canderous Ordo pledged his loyalty to the man he believed would bring him battles in which he could find honor, as he had in the Mandalorian War. Carth Onasi refused and ran away. Mission Vao refused to believe that Revan had returned to the dark side and did not run away. Zaalbar initially agreed to join the dark side as he owed Revan a "life-debt"; with the Force Persuade talent, Revan was able to force Zaalbar to kill Mission.
Before approaching the Star Forge, Bastila persuaded the Republic to attack the Sith fleet there as a measure to defeat the Republic. The Republic believed that she would use her Battle Meditation against the Sith, but she turned it against the Republic just before Revan faced Malak. Master Vandar realized all this but could not do anything.
After Revan defeated Malak, he reclaimed the title of Dark Lord of the Sith and Bastila became his apprentice. Together, they set out to conquer the galaxy.
Canonical Light Side Choice
Revan refused to give in to the dark side again. After an intense lightsaber duel, Bastila escaped with a G-Wing ship and returned to the Star Forge in rage and shame, where she and Revan eventually faced off a second time. Even though her powers were continually renewed by the Star Forge, Bastila found herself unable to defeat Revan. Beaten at last, she begged the former Dark Lord to take her life. Revan refused, however, and eventually persuaded Bastila to denounce the dark side and return to the light, drawing on the bond they shared--not one of the Force, but one of love. Bastila then used her Battle Meditation to turn the tide of the battle in the Republic's favor, allowing the Star Forge to be destroyed after Revan had slain his old friend Malak in personal combat.
After the battle, the Jedi reconvened, Bastila and Revan, along with their companions Republic soldier Carth Onasi, Twi'lek slicer Mission Vao, Zaalbar the Wookiee, astromech droid T3-M4, Mandalorian warrior Canderous Ordo, Juhani the Cathar Jedi, hunter-killer assassin droid HK-47, and former Jedi Jolee Bindo, were honored as the saviors of the galaxy.
Despite this seemingly happy ending, Revan and Bastila were not destined to remain together. A year after the Star Forge's destruction, Revan, having remembered a great threat to the galaxy he discovered as the Dark Lord, set out alone into the Unknown Regions, leaving all those he loved behind, for he knew that to take them to the places he had to go would bring destruction to them all.
Bastila remained behind with her fellow galactic saviors, keeping the Republic safe as Revan had asked them to, and waiting for the day when Revan would return.
KotOR II Dark Side Entrance
In the sequel to Knights of the Old Republic, if the player character specifies in the beginning of the game that Revan turned to the dark side, there is a chance to find a Sith Holocron in Uthar Wynn's room at the Sith Academy on Korriban. Once the exile goes into the room, the Holocron starts, and it seems that Bastila waited on Korriban in the Sith Academy for Revan to return. She says that she finally lost patience and left to go look for Revan.
KotOR II Light Side Entrance
In Knights of the Old Republic II: The Sith Lords, if the main character states that Revan went to the light side, after Darth Nihilus dies, the Exile will be questioned by Carth Onasi about Revan's fate. At the end of the conversation, Bastila will ask Carth about what the Exile told him.