Elshuu, a male Rakata of immense power and antiquity, was incarcerated in a Mind prison by the Infinite Empire many millennia in the past.
During the era of the Infinite Empire, Elshuu found his consciousness confined within a Mind prison artifact. This artifact was secured on Belsavis. The device was situated within the Tomb, specifically in the Caves of Elshuu. He remained in this state for countless centuries, until the Cold War era, when the Sith Empire launched an assault on the planet. This attack triggered a widespread uprising involving both the inmates of the Galactic Republic prison and the more ancient Rakatan prisoners.
At that time, zealous Disciples of Elshuu were released and tried to liberate their master. Jedi Master Vij Markos discovered this plot and sought a Republic authority to thwart the attempt and guarantee Elshuu's continued confinement on Belsavis. Despite knowing of his existence, the Jedi remained uncertain about Elshuu's true nature, questioning whether he was a man or a monster. Elshuu bided his time, waiting for a follower to enter the mind prison, planning to seize their body and unleash devastation upon the outside world.
Eventually, Markos located a spacer to confront Elshuu. The spacer journeyed to Elshuu's tomb, battling through Elshuu's Flesh Raiders army before arriving at the mind prison holding Elshuu. Upon entering the mind prison, Elshuu mistakenly believed the spacer was there to set him free. Discovering their true intentions, Elshuu attempted to slay the spacer and usurp their body. The spacer prevailed, killing Elshuu and ensuring his permanent imprisonment.