Jocasta Nu, a Force-sensitive human female, was a Master of the Jedi Order who served as the Chief Librarian of the Jedi Archives during the last years of the Galactic Republic. In this role, Nu was the primary caretaker of the extensive Archives, helping her fellow Jedi find the information they needed while controlling access to several restricted vaults and artifacts.

Although she was the Chief Librarian of the Archives, Nu was not removed from other Jedi affairs and, at some point, was a member of the Jedi High Council. As Chief Librarian, she worked alongside other Jedi such as Masters Tera Sinube and Eno Cordova. During the Clone Wars, Nu became involved in a plot by bounty hunter Cad Bane to steal a Jedi holocron, though she and her fellow Jedi failed to stop him from escaping the Jedi Temple with the artifact. She later helped Padawan Ahsoka Tano find the thief who stole her lightsaber, aided the Jedi Council in their investigation of Jedi Master Sifo-Dyas’ death, and continued to watch over the Archives.

At the war’s end, most Jedi were wiped out during the initial stage Great Jedi Purge and the rise of the Galactic Empire. Nu was among the survivors of the purge, and with her assistant Gar, attempted to preserve what knowledge she had and prepared a covert school to train future Jedi. Nu decided to return to the former Jedi Temple on Coruscant, knowing that hidden in the Archives was a holocron containing a list of force-sensitive children. Nu managed to sneak into the Temple and retrieve the holocron. Determined to put a permanent end to the Jedi, the newly crowned Emperor, Darth Sidious, dispatched his agents, Darth Vader and the Grand Inquisitor, to hunt down the former Chief Librarian. Knowing she wouldn’t be able to escape Coruscant, Nu attempted suicide but was foiled by Vader. Vader killed Nu afterward, though he later destroyed the holocron after Nu warned him of what Sidious would do with it.