Oni's not sure who nor what she is, and neither is anyone else, mainly because she appears to be made out of the shadows themselves. You have to be, in her business. Assassination and information seemed to be the most practical career choices for someone like her. Except, there's no one like her. Until she meets Xavier, her exact opposite. Where she is smoke and shadows, he is sunsets and light. He knows even less than she does, and she doesn't need any dead weight. However, she's stuck with him anyway. What will she do with him now that she has him? She was stuck with him the second he tackled her out of the sky.