Who should I be for Halloween? Saya or Diva from Blood+?

I want to be a girl character from Blood+ that has black hair. So i ask this question: Should i be Saya or Diva? I need it by September 30th. If you haven't seen the show before go to www.crackle.com and search Blood+. I don't care if it is Diva (evil) or Saya (good). Thanks!