Ezekiel Yith, Radiant Prism

For the first thousand years of the Radiant Empire, there was only one religion. Serviced by a single religious organization, the Sisters Illuminated, the Church of the Ascendancy viciously controlled all training related to the Radiance. Their enforcers traveled far and wide in the Empire's early days to either recruit or slaughter every hedge witch, mystic, or blade saint they could find. Their ruthless purge drove many radiant masters deep underground and killed tens of thousands of lesser practitioners.
The Church's absolute control over the illuminated was only possible because of the extreme dangers inherent in harnessing the higher powers. Most mortals who attempted the feat were either killed outright when their spirit was incapable of containing the strength they channeled or suffered debilitating shadow sickness when they inevitably lost control of their powers. The combination of great danger and persecution was enough to restrict the radiant arts to either the most deranged or witless mortals.
Ezekiel Yith changed all of that during a simple experiment gone horribly awry.
The young dragokith monk had spent most of his young life training at Starglow Monastery. The small installation, perched between the inhospitable White Talon range and the nearly as inhospitable Blightfoam Sea, was well-known for its scholarly articles on the nature of the Radiance and its interaction with mortals. Ezekiel had a particular affinity for this field of study, and often subjected himself to controlled doses of the sacred energy to study its effects. During his studies, Ezekiel discovered that Radiance underwent fundamental changes when it passed through a mortal spirit. Furthermore, this change could be detected by analyzing a subject's aura through a gemstone prism.
Ezekiel's studies revealed that Radiance was not a single source of energy. It was actually comprised of five separate hues that he chose to name after the type of gemstone prism that could detect them: sapphire, diamond, emerald, ruby, and obsidian. Furthermore, he discovered that most mortals were only compatible with one, at most two, radiant hues. Attempts to control incompatible energy types led to death or other impairments.The young monk's continued studies led him to the creation of the first Harness Screen, a simple item that restricts the flow of different hues of radiance. This made it far simpler for mortals to interact with the Radiance. The Sisters Illuminated soon learned of this breakthrough and attempted to have Ezekiel seized and his work destroyed before it could leak out into the broader world. The Church knew Ezekiel's tools would lead to a renaissance in radiant cultivation that would destroy their stranglehold on the mystic power.
Ezekiel got wind of the plot, however, and smuggled himself out of the monastery before the Sisters could capture him.  The instant he made landfall in Koyashotha, the monk publicized his discovery and word of his knowledge and methods spread like wildfire. At a stroke, Ezekiel had ignited the Age of Radiance and destroyed the Church of the Ascendancy.Sadly, assassins laid the brave young scholar low on the eve of his thirtieth birthday, depriving the world of any future discoveries he might have made.