How are the Diggers portrayed in the novel, Earthborn?

The Diggers are a sentient race on the Earth, depicted by their greater strength, claws, and the fact they dig and live in tunnels. The Diggers have their own earth-based religion that still has reference to the Keeper of the Earth and are depicted as some sort of marsupial-type creature. Throughout the story, the Diggers are either seen as cruel and ignorant, or as slaves to humanity.