In this world, color is magic. People who use this magic are called drafters. sub-red, red, orange, yellow, green, blue, and superviolet. Each hold their own unique qualities. But drafters have a limit, as they use their magic, their eye halos fill up. Once they draft more than they should, they break the halo and become a color wight. Normally leading to insantiy from being overtaken by their color. However, there is someone who does not have a limit. The Prism. Appointed by Orholam himself to serve the Seven Satrapies. As a leader of the Chromeria, the Prism gets chosen in years of seven to protect each nation. But things get rocky when the foundation of this belief becomes strain.
To learn more about this universe, read, "The Lightbringer" by Brent Weeks. It is a beautiful story with lots of thrills and twists and is absolutely one of my favorite books ever.