Hyperion by Dan Simmons

The universe of the Human Hegemony is under threat. Invasion by the warlike Ousters looms, and the mysterious schemes of the secessionist AI TechnoCore brings chaos even closer.

On the even of disaster, seven pilgrims set out on a quest for the legendary Time Tombs on Hyperion, home to the Shrike, part god and part killing machine with powers that transcend the limits of time and space. The pilgrims have resolved to discover nothing less than the secrets of the universe itself.