During the Empire's reign of tyranny, Jyn Erso had a troubling life from the age of fifteen. Due to her upbringing, she became a wanted criminal with a record of incidents, including the forgery of Imperial documents, possession of stolen property, aggravated assault and resisting arrest. After the Rebellion learnt about the construction of the Empire's new ultimate weapon, the Death Star, Chancellor Mon Mothma assigned Erso on a mission to steal the plans for this weapon, so they can get an insight on how to destroy it.
- “This is a rebellion, isn't it? I rebel.”
- ―Jyn Erso[src]
While growing up alone from the age of fifteen, Jyn is considered reckless and undisciplined. Having little patience for debate with Alliance High Command, she prefers to take matters into her own hands.
Even as a child, Jyn began developing a rebellious attitude but has a clear sense of right and wrong gained from her parents while growing up on Lah'mu. During her time with Saw Gerrera's insurgents, she developed a strong bond with the extremists.
Initially, Jyn cared little about the Rebel Alliance's cause, but after watching the hologram message from her father, Galen Erso, Jyn realized how important it was that the Galactic Empire be rid from the galaxy and sacrificed herself for their cause.
As a result of being trained by Saw Gerrera and being abandoned, develop calm yet cold demeanor, In addition, she is aggressive and distrusting, fighting off the Rebellion squad that was sent to rescue her, and keeping others at arms length until the battle at Scarif.
Despite her aggressive and cold demeanor, Jyn is intelligent, kind, caring, selfless, has a sense of justice, honor and good morals.
Jyn's relationship with Cassian Andor was initially complicated, as the two didn't trust one another when meeting. After learning that the immoral rebel general Davits Draven ordered him to kill Galen, she learned of his experience from the war, and the two would later become respectful allies once they disobey orders and headed to Scarif. Her relationship with K-2S0 was distasteful, with the latter having restrained her when she attacked the squad that was sent to rescue her. Despite this, K-2S0 showed himself to care for Jyn, saying he will do anything for her, and sacrificing himself for her and Cassian in his last moments.
- Expert Hand-To-Hand Combatant: While growing up alone from the age of fifteen, Jyn developed fighting skills. His abilities are useless against the droids like K-2SO.
- High-Level Intellect: While growing up alone from the age of fifteen, Jyn developed a keen knowledge of the galactic underworld.
Jyn first appears as a young girl on Lah'mu. When Orson Krennic and some Death Troopers arrived, Galen Erso told his daughter to run away with her mother. On the way her mother Lyra asked her to go hide and handed her daughter her kyber crystal necklace. Jyn follows her mother and sees Director Orson Krennic order his troops to shoot Lyra and capture Galen. She runs quickly and hides in a secret bunker while she awaited the arrival of Saw Gerrera.
More than a decade later, Jyn was arrested and jailed for more offenses against the Empire. During her transfer to a labor camp, the vehicle was attacked by rebels which was specially for her. The chief disarmed her handcuffs and was distracted by a another prisoner, so Jyn attacked her saviors and tried to flee but was tackled to the ground by K-2SO. Then Jyn embarked the rebel ship flying to Yavin 4.
Mon Mothma asked Jyn to go to Jedha to speak to Saw Gerrera who had received a message from Galen by an imperial pilot who had deserted. Accompany by K-2SO and the captain Cassian Andor, went on the planet and after a fight with Stormtroopers, Jyn and Cassian were captured by the men of Saw Gerrera, and thus were led to his hiding place.
After a brief conversation with his old friend, Jyn looked at her father's holographic message, which explained that there was a flaw in the Death Star - a powerful weapon capable of destroying planets. When the message was completed, a laser beam of the Death Star reached Jedha City and caused a terrible earthquake all around. Jyn fled with the other rebels while Saw stood hus ground, preferring to face his death.
Jyn and her companions then travel to Eadu to find Galen. Jyn leaves the ship and heads for the Imperial station where her father was located. After climbing a staircase she knocked down a Stormtrooper and stole his weapon as the rebellion-allied ships arrived and began to bombard the station. Galen was caught in the explosion, severely wounding him. Jyn took her father in her arms until his last breath.
At the briefing at the rebel base, Jyn attempted to convince the alliance to help her steal the Death Star's plans to destroy it, but unfortunately the decision was not unanimous. Once out, Jyn was glad to see that Cassian trusted her and had gathered several people to try to steal the Death Star's plan.
Once on Scarif, Jyn and Cassian stun two Imperial agents and Stormtroopers and stole their armor to enter the building unharmed, accompanied by K-2SO. While the others created a diversion outside, the trio arrived at the archives. K-2SO remained on guard while Jyn and Cassian entered the command room of the archives. After having locked the door to prevent the Stormtrooper reinforcements from reaching Jyn and Cassian, K-2SO was killed by their blaster bolts. After the duo entered the other side of the control room to physically retrieve the Death Star plans, Director Krennic arrived with two Death Troopers and attempted to fire at them. Cassian was knocked unconscious in an attempt to distract them as Jyn reached the top of the tower.
Once outside the tower, she used the computer to transmit the plans to the rebel ship which had arrived, but Jyn was confronted by Krennic. She told him that the rebels had already won, but Krennic replied that she was mistaken and aimed his blaster at Jyn, but before he could pull the trigger, Cassian fired at Krennic, having regained consciousness. Jyn finally transmitted the plans to the rebels and made their way to the shore as the Death Star, directed by Tarkin, fired at Scarif. Jyn and Cassian embraced each other and they were finally killed by the explosion that engulfed them.
In the episode "A World Between Worlds", Jyn Erso makes a vocal appearance. As Ezra Bridger is wondering in the Word Between Worlds, it is possible to hear her voice saying "The time to fight is now!" which she says to the members of the rebel alliance to convince them not to surrender in Rogue One, although this is an event set in the future.
Jyn appears in the animated miniseries, Star Wars: Forces of Destiny, with Felicity Jones reprising her role. In "The Stranger", set before the events of Rogue One, Jyn aided a little girl when Stormtroopers tried to take away her Loth-cat.
Jyn Erso is a playable character in Star Wars: Force Arena as a Legendary squad leader card.
- According to director Gareth Edwards, Jyn Erso's mother was originally a Jedi Knight and that Krennic was to murder her. This was eventually written out due to the possibility of it becoming confusing as to whether or not Jyn was a Jedi and by extent Force-sensitive.