- "An old friend has learned the path to immortality. One who has returned from the Netherworld of the Force."
The Netherworld of the Force was the place the souls of Force-sensitives were thought to ascend to after their physical bodies died. The Jedi Master Qui-Gon Jinn went to this realm after he was killed by Darth Maul, but, thanks to the help of the Force Priestesses, he managed to return from it back to the physical universe as a Force spirit.
- Star Wars: Episode III Revenge of the Sith (First mentioned)