Emperor Mage by Tamora Pierce

Book 3 of the Immortal's series

When Daine is sent to Carthak as part of a Tortallan peace delegation, she finds herself in the middle of a sticky political situation. She doesn't like the Carthaki practice of keeping slaves, but it's not her place to say anything-she's only there to heal the emperor's birds. Her worries only expand once she learns that her own power has grown in a dark and mysterious ways.

As the peace talks stall, Daine puzzles over Carthak's two-faced Emperor Ozorne. How can he be so caring with his birds and so cruel to his people? Daine is sure he's planning something-a terrible, power-hungry scheme. And she knows that she must fight this powerful Emperor Mage; the life of her beloved teacher is at risk.

Wolf Speaker by Tamora Pierce

Book 2 of the Immortal's series

When Daine is summoned to help a pack of wolves-dear friends from her old village- she and Numair travel to Dunlath Valley to answer the call. But when they arrive, Daine is shocked to learn that it's not only animals whose lives are threatened; people are in danger too.

Dunlath's rulers have discovered black opals in their valley. They're dead set on mining the opals and using the magic contained in the stones to overthrow King Jonathon. Even if it means irreversibly damaging eh land- and killing their workers.

Daine must master he wild magic in order to save both her animal friends and her human ones.