Aww, i had a feeling you;d choose her! I think it'd be really fun to work on her back story a little more! Add Yuki and give them a little more purpose :3
It would be nice to know more about! ^^ I'm not saying I don't care about your other characters, but I tend to veer towards fantasy-like, unique and stand-out characters. In the case of yours, it's the ninja stuff that intrigues me. :3