Wheel of the infinite
Maskelle is the voice of the adversary, but the adversary appears to have abandoned her many years ago after sending her a false vision.  Now she has been asked to return to the capital in order to repair the 100 year rite that has been damaged.  The consequences to her world and the adversary, if she fails, will be earth shattering (hah!).
Fantasy fiction, Fiction, science fiction, general
Martha Wells
Martha Wells (born September 1, 1964) is an American writer of speculative fiction. She has published a number of fantasy novels, young adult novels, media tie-ins, short stories, and nonfiction essays on fantasy and science fiction subjects. Her novels have been translated into twelve languages. Wells has won a Nebula Award, two Locus Awards, and two Hugo Awards.