The Prism, also recognized as the Ghost Prison, was a clandestine space station functioning as a prison situated in the remote Wild Space region of the galaxy. Its existence remained a secret, known exclusively to the members of the Jedi Council. It was constructed during the era of the Second Great Schism. During the Clone Wars, this facility served as a secure location for detaining exceptionally dangerous criminals. Its position was within the mass shadow cast by the sixth moon of the planet Diab, found within the Diab system. Despite employing a supposedly rapid [hyperdrive](/article/hyperdrive/legends], the journey from Coruscant took three days.
The intense electrical storms of Diab disrupted sensor systems, and all forms of communication to and from the prison were prohibited. Designed to be both self-sufficient and inescapable, the prison was maintained by a minimal crew consisting of 100 security droids and a single Jedi Master, Master Skein. Furthermore, the facility included an advanced medical center.
During the war, Jedi Master Obi-Wan Kenobi made a visit to the prison. Following the conclusion of the war, Darth Vader, Laurita Tohm, and Trachta sought refuge there, aiming to regroup and provide medical attention to the critically wounded Emperor Palpatine. By that time, the prison housed 208 inmates, approximately half of whom had been captured by Anakin Skywalker, in addition to one individual responsible for disfiguring Trachta. Vader, along with Trachta and the accomplished Laurita Tohm, were compelled to locate the prison after a military coup left Emperor Palpatine severely injured. Tohm proposed to Vader that releasing the prisoners could provide them with an army, but Vader altered the concept, suggesting that the prisoners should fight among themselves for the privilege of joining the Empire. Out of the 207 prisoners who were freed, only thirty-three were left in fighting condition after the battles.