“The war raged across the galaxy. Billions had died, billions more were doomed. Moons, planets, the very stars themselves, faced destruction, cold-blooded, brutal, and worse, random.”
NO MAJOR SPOILERS
There is war between the Indirans and the Culture and at the stage we start to read the book, the Indirans seem to be getting the upper hand.
The Indirans: They are a tripodal species that revere their own god and believe that life should be governed by life, not machines. They are also expanding their empire and have come up against the Culture.
The Culture: A humanoid society run mainly by sapient machines that were originally designed and built by the humanoids but now design and manufacture themselves for the sole benefit of the humanoid societies. Humanoids live a life of leisure unless they choose to work, they can also live up to and beyond 400 years old through manipulative surgery.