Darth Bane: Rule of Two, the sequel to the novel Darth Bane: Path of Destruction, is part of the Star Wars expanded universe. It was written by Drew Karpyshyn, and was released on December 26, 2007. The novel centers on the young Sith apprentice Darth Zannah, recently taken under the wing of the Sith Lord Darth Bane. The "Rule of Two" of the title refers to the rule that there be only two Sith in existence at one time: a Master and an Apprentice, a rule that Bane originates.