The EN World kitten
Basically, they were constructs made by the aasimons (i.e. angels) to watch over important treasures, until the quesars decided that they wanted more out of existence than to be automatons. There's a good article about them over on the Forgotten Realms wiki:What were they like? curious
Quesars were living constructs of light created by the aasimon. Some described quesars as stars brought to the ground. These gaunt humanoids shined with an intense light that would blind most creatures and extend for about 40 feet (12 meters) from their bodies. Behind the radiant glow, a quesar...
You can also still find the page with the web enhancement thanks to the Wayback Machine: