Koukyuu no Karasu

Koukyuu no Karasu (後宮の烏) is a light novel series written by Kouko Shirakawa and illustrated by Ayuko. It is published by Shueisha under their Orange Bunko imprint. An anime adaptation has been announced.

Plot
Deep within the inner palace lives a special consort who does not serve the emperor despite her position, known as the Raven Consort. People who have seen her say she looks like an old woman, while others say she looks like a young girl. Stories talk of her use of mysterious arts and how she can take on any request, be it death curses to finding lost things. Koushun, the current emperor, goes to visit the Raven Consort with that intention, without knowing that their fated meeting will become a taboo that will overturn history.

Official

 * Novel website