Ancilla is entered into Best Original Idea because, let's face it, Ancilla is nothing if not original. 

The characters have no names.

The book is structured on the Kabbalistic Tree of Life. It's metaphysical smut.

It's written mostly in a highly organized stream-of-consciousness style. 

The male main character is a vampire and magus who happens to be a sexual sadist and dominant. And a librarian. And almost ludicrously wholesome and unproblematic. He is like milk and cookies and warm hugs and library books embodied in a 6'2", rail-thin, kinky middle-aged package.

Is dark academia/ magical realism/ mysticism and metaphysics/ literary BDSM erotica/ bisexual bildungsroman/ slice-of-life/ Generation X nostalgia/ multiple nerdgasm/"I wrote this to destroy the dark romance genre and all its toxicity, and to put E L James and her followers in their place" a genre? 

100% original.