Thorn Jack: A Night and Nothing Novel
The Fatas in Thorn Jack call themselves 'the children of night and nothing' because they believe they CAME from nothing and night, that they are thought-forms and elementals that only take on substance when they find a belief system they can shape themselves into. Or perhaps they are the ancient dead, spirits who haven't passed on and have evolved.
The Fatas are based on the faeries of Celtic and Gaelic folklore, who are entwined with the dead, the old gods, and mythical monsters. But each country has their own tribe or court of Fatas, reflecting the historical culture of the place in which they exist. The French Fatas call themselves 'La Bestia', because their favorite shadow form is that of a wolf, yet they are elegant and modern. The native Fatas of America call themselves Blackhearts because of what happened to the original inhabitants with whom they used to communicate.
But Finn and Jack's Fatas are outlaws and criminals, banished from their various countries to the 'New World', where the Blackhearts generally have nothing to do with them they wear the shapes of dreams or nightmares. Rules keep them in those shapes and they must adhere to those rules.
And in order to survive these capricious and sometimes malevolent entities, Finn and her friends must learn the rules.