The Goddess Chronicle (Canons) by Natsuo Kirino

On an island in the shape of a teardrop live two sisters. One is admired far and wide, the other lives in her shadow. One is the Oracle, the other is destined for the Underworld. But what will happen when she returns to the island? Based on the Japanese myth of Izanami and Izanagi, The Goddess Chronicle is a fantastical tour de force about ferocious love and bitter revenge. The Myths series brings together some of the world's finest writers, each of whom has retold a myth in a contemporary and memorable way. Authors in the series include Karen Armstrong, Margaret Atwood, A.S. Byatt, David Grossman, Natsuo Kirino, Alexander McCall Smith, Philip Pullman, Ali Smith and Jeanette Winterson.