Star Wars: Episode I – The Phantom Menace be told in sequels on the chance that it became successful, so "Star Wars" evolved from the first film in the series to the first episode of the saga's second trilogy. Lucas eventually negotiated a contract that allowed him to make two sequels, and over time had created an elaborate backstory to aid his writing process. While writing "The Empire Strikes Back", Lucas considered directions in which to take the story. In the original trilogy, Darth Vader was revealed to have been Anakin Skywalker, a once-powerful Jedi Knight, and a traitor to the Jedi Order. With this backstory in place,
Star Wars: Episode III – Revenge of the Sith state to fight a Sith Lord. These are a few examples of many descriptions of characters' feelings and inner narrative. There are even some humorous lines added in, including extra dialogue in the battle between Grievous and Obi Wan - Grievous says, "I was trained by Count Dooku," and Obi-Wan replies, "What a coincidence; I trained the man who killed him." An official prequel novel, "Labyrinth of Evil" () by James Luceno, was published in 2005. It is set near the end of the Clone Wars and directly before the events of "Star Wars: Episode III Revenge of the Sith".