Consider Phlebas

The war raged across the galaxy. Billions had died, billions more were doomed. Within the cosmic conflict, there was an individual crusade: deep within a fabled... » 

The war raged across the galaxy. Billions had died, billions more were doomed. Within the cosmic conflict, there was an individual crusade: deep within a fabled labyrinth lay a fugitive Mind. Both the Culture and the Idirans sought it. «