Jiaasjen represented a religious concept and philosophy embraced by the Jensaarai movement, with its origins attributed to Larad Noon. It was believed that the term was a Sith expression, which meant "integrating the shadow," and it pertained to the idea of incorporating the doctrines of the dark side of the Force into the application of the light side. This was akin to the notion held by Count Dooku, who believed a perfect being could utilize both aspects of the Force in equal measure.
The Jiaasjen philosophy was conceived by Larad Noon, a survivor from the Brotherhood of the Sith. He was burdened by immense remorse for his actions during the Great Sith War. Noon formulated this theory as a means to justify his past transgressions and maintain his sanity. He dedicated himself to writing extensively about Jiaasjen during his self-imposed isolation on the planet Susevfi until his passing.
Millennia later, during the Clone Wars, followers of the Jensaarai, who followed the recently deceased Nikkos Tyris and were led by a female Saarai-kaar, journeyed to Susevfi in pursuit of Sith knowledge. By chance, they discovered Noon's writings concerning "integrating the shadow." With no other instructor available, the Saarai-kaar integrated his teachings into her own beliefs, giving rise to a Force cult that exhibited characteristics of both the light and dark sides.
- Evil Never Dies: The Sith Dynasties on Hyperspace (article) (content now obsolete; backup link)
- The Complete Star Wars Encyclopedia