Chaos
The Chaos, also called Hell or The Void, is an existing plane of existence from Legends.[1]
Palpatine referred to the period between his death and rebirth as "passing through the Chaos." On his orders, Mas Amedda studied writings and holocrons pertaining to the Chaos, among them records from Xendor, Darth Andeddu, and Darth Plagueis.[2]
The physicist and Church of the Dark Side devotee Sigit Ranth envisioned the Chaos as being identical with hyperspace. As a result, Ranth had trouble looking at hyperspace without imagining the souls of the dead being ripped apart. Ranth also hypothesized that Force lightning was the Chaos leaking into reality.[2]
Immediately after his death, Anakin Skywalker was sheltered in the Chaos by the spirit of Obi-Wan Kenobi, allowing him to keep his essence together and look out into the real world for a short while. The spirits of Yoda, Qui-Gon Jinn and others were creating islands of stability within the Chaos. However, Anakin was soon attacked and separated from the Jedi spirits by Palpatine's spirit, who forced Anakin to feign submission to him.[3]