Xa'an was the Light and the light was Xa'an. He was light made aware. However, after the death of Xa'an by the God of Knowledge Veros the light was passed on to the God Drahthor who then claimed the domain of Fire in an attempt to reconcile these two elements.
The Light Domain generally manifests itself by the holder glowing. The holder controls the spread of light and, of occasion, the suppression of light.
Those who fear darkness pray to the god of light to banish it.