Who is Rachel Weintraub from The Rise of Endymion and what is their importance?

Rachel Weintraub was one of the original Hyperion pilgrims. When the group arrived on Hyperion, Rachel was an infant. Later, she was exposed to an anti-Time field from Hyperion's Time Tombs while studying the tombs as a graduate student. From then on, she aged backward, becoming younger and younger, until, as an infant, she was given to the Shrike by her father. She later returned from the future to guide Fedmahn Kassad to his destiny, and then returned once again to become Aenea's follower.