I was a little disappointed by the lack of specific races in the book.
So I decided to do some reskinning!
I am planning on playing a Dryad: they are iconic Ravnican creatures, and the Eladrin, with their seasonal changes, suit them to a T. The idea is that she was meant to be the leader of a nascent Vernadi that got destroyed. A Golgari took her in from when she was a sapling and raised her to believe that the Selesnya abandoned her. She now has vowed vengeance on the people of the surface, but also can interact with them with less prejudice than most obviously "golgari" races, making her an ideal spy/assassin for the Ochran.