Nation (novel)
Mau believes he can hear the voices of "the Grandfathers", who are old men whose spirits watch over the Nation.  They order him around telling him to rebuild the Nation's god-anchors (altars) and perform the rituals and chants that made up the culture.  Many of the characters in the book ask whether God or the gods are real because they allowed a bad thing to happen: the wave that killed so many people.  Mau often says he doesn't think the gods exist, but he can see the god of death, Locaha, who talks to him.