this character is an actor, I think she is human but it doesn't matter if she is or isnt, her character is the kind that is too nice and perfect and likable so when playing this role dont come across as mean or bitchy, she is just super nice and lovable despite being on an antagonists side.

her voice can be anything you want just so long as her personality shows through in your acting 

here is here she shows up in the comic please read this and use it when recording 

http://mangaseeonline.us/read-online/Soulless-chapter-1-page-26.html

have fun and good luck