Darth Bane's apprentice

"I chose to pass my knowledge on to only one. I created a legacy so resilient that now, you come before me."

- An illusion of Darth Bane to Yoda

This individual was a Sith apprentice trained by Darth Bane to carry his teachings forward after a war between the Sith and the Jedi Order. The apprentice was the first to be instructed as part of the Rule of Two, which mandated that there could be only two Sith&mdash;a master and an apprentice&mdash;at any given time. This apprentice escaped the notice of the Jedi. After the Jedi defeated Bane, his apprentice carried on the Rule of Two, which allowed the Sith to survive in secret.

Behind the scenes
Darth Bane's apprentice was first mentioned in Terry Brooks' novelization for Star Wars: Episode I The Phantom Menace, based on backstory notes by George Lucas. While the novel mentions the character as male, Darth Bane's apprentice was established as female in the Star Wars Legends Expanded Universe, first appearing in Jedi vs Sith as the Jedi youngling Rain, and named Darth Zannah in the Darth Bane trilogy.