Luminus was a human cult created by Faction Paradox in the distant future. (FP: The Book of the War)
They established themselves on many worlds, controlling all aspects of society wherever they ruled. Shortly after one planet, Olleril, was colonized, Luminus was apparently overthrown, but in fact they continued to rule the planet in secret. The cult was later taken over by Crispin, who plotted to establish his own version of perfect order on Olleril, but was defeated by the Doctor, and the power of Luminus was broken. (NA: Tragedy Day)