Force spirits, also known as Force ghosts, were beings who gained immortality through the preservation of their consciousness after death. When lifeforms died, they became one with the Force. Through special training, however, deceased Force-sensitives could retain their identity and, therefore, communicate with the living. By achieving spiritual immortality, a person’s physical form would vanish upon their death. This knowledge could be learned only by those who fully embraced the light side of the Force, such as the Jedi who lived by a code of selflessness and sacrifice. The followers of the dark side of the Force, such as the Sith, were incapable of learning this power, though there were many techniques open to them that offered similar benefits.
Before the Fall of the Republic, Jedi Master Qui-Gon Jinn learned the ability to become a Force spirit from the Shaman of the Whills, but was killed by Darth Maul before he could complete his training. As a result, for a time he could only commune with the living as a disembodied voice. Near the end of the Clone Wars, a conflict in which the Galactic Republic and Jedi Order were at war with the Separatists, Grand Master Yoda embarked on a spiritual journey that brought him to the planets Dagobah and Moraband—as well as the birthplace of the midi-chlorians—and ultimately learned how to retain his identity after death. This ability was also learned by Jedi Master Obi-Wan Kenobi during the rise of the Galactic Empire. Qui-Gon subsequently mastered the ability to manifest in an almost solid form. Although Anakin Skywalker—a fallen Jedi Knight and the Chosen One of the Force—never received the training that allowed his mentors to become Force spirits, his redemption and sacrifice made it possible for his consciousness to be preserved after death by Kenobi and Yoda, much like how his grandson became a Force spirit in 35 ABY. In 34 ABY and 35 ABY respectively, Luke and Leia—Skywalker’s biological children—attained immortality like their father.