The Netherworld of the Force, also referenced as the Mist-Beyond, the Garden Beyond, or simply the afterlife, was considered to be the destination that the souls of all beings and entities would journey to upon the death of their corporeal forms.
While linked conceptually, Chaos was a distinct and undesirable mythical realm, separate from the Netherworld. In the period between 40 and 32 BBY, Darth Sidious, the Dark Lord of the Sith, became aware of a cult called the Final Occultation. This cult, allegedly aided by chaotic forces originating from the Netherworld, aimed to supplant the systems of order within the Force with chaos, intending to inflict madness and anguish upon the Galaxy. However, Darth Maul, Sidious’s apprentice at that time, destroyed the cult before they could achieve their objectives.
Following his death at the hands of Darth Maul in 32 BBY, the Jedi Master Qui-Gon Jinn journeyed to the Netherworld. Subsequently, with the assistance of the Force Priestesses, he was able to return to the physical universe as a Force spirit.
The concept of the Netherworld of the Force was initially introduced in the 2005 movie Star Wars: Episode III Revenge of the Sith, which served as the concluding chapter of the Star Wars prequel trilogy. Nevertheless, George Lucas had already conceived the Netherworld in the early stages of the revised rough draft for the 1983 film Star Wars: Episode VI Return of the Jedi.