Consider Phlebas (Culture, #1)

Iain M. Banks

Set against the backdrop of the devastating Idiran-Culture War, this space opera follows Bora Horza Gobuchul, a shape-shifting mercenary working for the deeply religious Idirans against the Culture—a sprawling, post-scarcity civilization governed by hyper-intelligent AIs. Horza is tasked with retrieving a fugitive Culture Mind from a forbidden Planet of the Dead, plunging him into a violent odyssey across a galaxy at war. The first novel in Banks's legendary Culture series.