Jerec was a powerful Miraluka Jedi Master and Jedi archaeologist who turned to the dark side under the Empire, becoming a feared Inquisitor during the Galactic Civil War. Jerec was apprenticed to a Jedi archaeologist, Jocasta Nu, and became a Jedi archaeologist himself, versed in knowledge of the Jedi's past, especially the Sith. A Jedi Master during the Clone Wars, he was on a long-term deployment searching for ancient knowledge in the Unknown Regions when Order 66 was issued. Upon his return, Jerec was found by the Inquisitorius and turned to the dark side.
Jerec served the Empire as an Inquisitor for many years. However, Jerec was in truth devoted only to himself. One of the most powerful Dark Jedi in the Empire, Jerec continually sought ways to increase his power and take the Empire for himself. One of his chief obsessions was the Valley of the Jedi on the lost planet of Ruusan, which contained vast amounts of trapped Force power. After the Emperor's death at Endor, Jerec formed a band of seven Dark Jedi to seek out the Valley. He was able to find the legendary well of energy, and reached incredible heights of power by basking in its aura. However, for all his power, he was defeated in combat by Kyle Katarn, a novice Jedi who fulfilled an ancient prophecy, regarding freeing the Valley's trapped Jedi and Sith spirits. When Katarn offered him his fallen lightsaber in a final act of mercy, Jerec made one last attack and was struck down in the heart of the Valley.