During the time of the Clone Wars, the Jedi Master known as Yoda embarked on a quest to Moraband. This planet, the old homeworld of the Sith, was his destination as he sought to uncover the mysteries of eternal consciousness within the Force. As part of his tests to be found deserving of learning the secrets of immortality, Yoda had to confront his deepest fears while on Moraband. Yoda also desired to discover the true identity of Darth Sidious, who was the Dark Lord of the Sith and the hidden orchestrator of the Clone Wars.
When Yoda arrived on Moraband, he was met with illusions of Sith spirits, and also the ghost of Darth Bane, the ancient Sith Lord responsible for establishing the Rule of Two. Following this, Yoda experienced a vision of Sifo-Dyas, the Jedi Master who originally commissioned the creation of the Grand Army of the Republic. This vision was crafted by Darth Sidious and his apprentice, Count Dooku, who observed Yoda's progress from a distance. Sidious then generated another illusion, showing Yoda leading Jedi in a confrontation against Sidious on Coruscant. Within this vision, Yoda had to choose between allowing Anakin Skywalker to perish in order to defeat the Dark Lord, or sacrificing his own life to save his comrade. Yoda chose to give up his own life, which resulted in the successful completion of his trials. Ultimately, Yoda would discover the secrets of eternal consciousness, allowing him to return as a Force spirit after his physical death.