The Rise of Endymion ( Hyperion Cantos #4 ) by Dan Simmons [Mass Market Paperback]

"The magnificent conclusion to one of the greatest science fiction sagas of our time
 
The time of reckoning has arrived. As a final genocidal Crusade threatens to enslave humanity forever, a new messiah has come of age. She is Aenea and she has undergone a strange apprenticeship to those known as the Others. Now her protector, Raul Endymion, one-time shepherd and convicted murderer, must help her deliver her startling message to her growing army of disciples.
 
But first they must embark on a final spectacular mission to discover the underlying meaning of the universe itself. They have been followed on their journey by the mysterious Shrike--monster, angel, killing machine--who is about to reveal the long-held secret of its origin and purpose. And on the planet of Hyperion, where the story first began, the final revelation will be delivered--an apocalyptic message that unlocks the secrets of existence and the fate of humankind in the galaxy."