Witch World Series 4: Secrets of the Witch World Series by Andre Norton, Lyn McConchie

All of Witch World knows to fear the hated, fire-eyed Keplian horses who lure riders to their deaths. All that is, save for one young Native American girl new to Witch World, who rescues a Keplian mare and her foal and discovers an awesome truth--the Keplians were created to serve light, not darkness, and to ride with humans. This is the first in a new trilogy.

All of Witch World knows to fear the hated, fire-eyed Keplian horses who lure riders to their deaths. All that is, save for one young Native American girl new to Witch World, who rescues a Keplian mare and her foal and discovers an awesome truth--the Keplians were created to serve light, not darkness, and to ride with humans. This is the first in a new trilogy.