This is a theological fiction; like Terry Pratchett's 'Small Gods', it points to a polytheistic world in which the gods have a strongly symbiotic relationship with their believers. But while Pratchett's Discworld is comic, the world we have here is epic, veering towards tragedy. The gods had enslaved all but their true believers, and had had to be eliminated. The story hangs upon whether that elimination had been final or whether, in some form or other, the gods had survived.