Xanetia is the Anarae (Princess, sort of) of the Delphae, a people derived from the Tamul race but changed by their god, Edaemus. Like Styrics, Delphae life cycles are extended compared to Elenes; she is noted as looking no more than 16 when she is in fact over 100 years old. She first appears in The Shining Ones (said title is another name by which the Delphae are called). When Sparhawk and company realize they are being herded by the Delphae, Xanetia offers herself up to them as a hostage to prove they mean no harm. She becomes the representative of their people and explains their situation and request.
In return for their services in helping to stop Cyrgon, they wish Sparhawk to beseech Bhelliom to seal their city of Delphaeus from the outside world so none may enter or leave. Xanetia's unique talents prove critical in the latter half of The Tamuli. Like all Delphae, her natural form is humanoid and Tamul in appearance but with a bright white aura coming from within (thus why Delphae are known as "Shining Ones"). Originally nothing more than that, when people turned against the Delphae in the distant past for reasons never stated, Edaemus turned the glow into a warning and a curse—her very touch can cause the immediate decay of any life form. In addition, Xanetia can manipulate both the light within (so as to disguise herself as a normal Tamul) and the light around her (to make herself nearly invisible). She can also, if necessary, alter her physical form; though most Delphae use this to create disguises, Xanetia uses this ability to morph into mist in The Hidden City. Most notably, she can read (what she calls "share") the thoughts of any person she sees. It is this latter that helps to unravel the conspiracy against the Tamul Empire as well as reveal Zalasta as a traitor. Also, because her magic power was made into a curse, her aura and magic have the peculiar ability to mask other magic, including that of Bhelliom itself.
At the end of the Tamuli, the Delphae's wish to seal their city becomes unnecessary. With help from Bhelliom, the evolution of Xanetia and the rest of the Delphae is accelerated, and they leave the world with Edaemus and journey to the stars.