Jocasta Nu was a female Jedi Master of the Old Republic in the decades before the eruption of the Clone Wars. As a Jedi Knight, Jocasta Nu served as an archaeologist in the Jedi ExplorCorps, a organization operated by the Jedi that was responsible for exploring the Unknown Regions. During her travels, Jocasta Nu discovered a young Miraluka child named Jerec who was strong in the Force, as many of his species were. Jocasta took the young boy as her Padawan and trained him to knighthood. Sadly, with the fall of the Jedi Order, so too Jerec would fall and plague the galaxy as a Dark Jedi in the years following the defeat of the Empire.

Following her service as a Jedi archaeologist, Jocasta Nu served on the Jedi Council for ten years before stepping down to serve as the Chief Librarian of the Jedi Archives. When Jocasta Nu left an active Jedi lifestyle behind, she also left the traditional Jedi robes behind and donned garments that highlighted her dedication to knowledge and learning. One of her favorite garments depicted Ansata symbols. The Ansata were a race of beings known throughout the galaxy for their own devotion to knowledge and learning.

While Master Nu may have left the active Jedi lifestyle behind, she was by no means inactive as Chief Librarian of the Jedi Archives. Not only did she possess an extensive knowledge of the information contained in the archives, Master Nu was always on hand to prepare mission briefs for Jedi Knights and Masters, as well as assist those doing their own research. During her time in the archives, Master Nu tutored Jedi Knight Olee Starstone before she was apprenticed to Jedi Master Bol Chatak.