According to the Jedi tradition, death was a part of life, and it meant becoming one with the Force. In death, sentients lost their ability to communicate with the living, but mastery of certain obscure paths of learning could avert it.
The origins of that knowledge, as well as its history, are not known. Ancient Jedi of the
Galactic Republic such as
Arca Jeth, as well as Sith Lords, knew a secret which could enable the user's essence to "survive death", but this knowledge was somehow lost over the millennia. However, it was secretly preserved over the millennia by the native
Ysanna, descendants of Jedi trapped on the world and slowly driven to barbarism.
Rediscovery
Qui-Gon Jinn was the first of the recent Jedi who rediscovered this secret with the assistance of a
shaman of the
Whills. Qui-Gon's spirit guided
Yoda (Leading him to meet the five priestess) and
Obi-Wan Kenobi and revealed to them the secret of retaining one's individuality after becoming one with the Force. Yoda during his exile taught it to another
Jedi Master,
Qu Rahn.
The Dark Woman also learned of it at some point.
Death for those Jedi were different: their spirits could retain their individuality and could return as voices, dreams, or apparitions at will, so that they could help those in need of their guidance. On death, their bodies vanished; this was not the case with Qui-Gon, however.
<img src="http://vignette4.wikia.nocookie.net/starwars/images/a/a1/Obi-Wan_Kenobi_SWGTCG.jpg/revision/latest/scale-to-width-down/200?cb=20090331174011" alt="Obi-Wan Kenobi SWGTCG" class="thumbimage " data-image-key="Obi-Wan_Kenobi_SWGTCG.jpg" data-image-name="Obi-Wan Kenobi SWGTCG.jpg" width="200" height="150" >
Obi-Wan Kenobi, as he appeared on
Mustafar.
This state was temporary, as Force ghosts were an intermediate state between life and afterlife; after a certain amount of time, they would then have to move on to the
Netherworld of the Force, another realm of existence.
Darth Vader learned of this ability through
Darth Sidious, and upon his death, the spirits of Kenobi and Yoda completed his training by granting him the last step in becoming a spirit. Anakin's spirit appeared as that of his younger self, prior to his fall to the dark side.
Similar techniques
Certain
Sith Lords had also discovered similar techniques. Occasionally their bodies would fade as Jedi would, though like Jedi this was not a prerequisite for becoming a Force ghost. It was not uncommon for the spirits of Sith Lords to remain, bound to the living world through an object, location, or simply due to the force of their malice and hatred. Unlike the Jedi, however, the Sith found little peace in this form, instead existing for restless centuries, eventually driven insane by solitude, memories, or dark side inflicted madness. In many ways, these techniques differed from those taught by the Jedi; the most distinct difference being the user's limited ability to interact with his surroundings. One proficient Sith user of these techniques was
Exar Kun.
Notable Sith such as
Darth Andeddu and
Darth Bane feared their own mortality rather than embracing it and becoming ghosts of the Force such as their Jedi counterparts. Due to this fact they sought ways to escape death and live on indefinitely. Though there was much speculation, Bane's body did not disappear and become one with the Force when he died. His soul was absorbed into his apprentice's body and dominated by her soul leaving behind only a trace of his soul. In this case and many others the Sith lived on only in the small essences of their souls that they embedded into their
Sith holocron's. Where as the many Jedi who believed that there was no death only the Force lived on forever through the acceptance of their death. The Sith believed that the Force would free them and break their chains that bound them to their mortal coil.
[7]
Luke didn't die, maybe he can get a force ghost hand.
<img src="http://vignette4.wikia.nocookie.net/starwars/images/a/a1/Obi-Wan_Kenobi_SWGTCG.jpg/revision/latest/scale-to-width-down/200?cb=20090331174011" alt="Obi-Wan Kenobi SWGTCG" class="thumbimage " data-image-key="Obi-Wan_Kenobi_SWGTCG.jpg" data-image-name="Obi-Wan Kenobi SWGTCG.jpg" width="200" height="150" >
@Darqnezz said. It's kind of a power that has been used in the Star Wars universe to more or less allow certain dead characters to influence the stories still. The specifics are bent to whatever story you're reading/watching/playing, but the constant is that the person has to be a Jedi/Sith and has to die. If not, they just get diced up and injured like everyone else. And I'd rather have a super strength robo-hand than a creepy, cold ghost hand any day.
