Rachel is interested enough to regard the elder vampire back for a moment but knows better then to hold her gaze for any longer then that. Blackstar was likely older then her Sire who had been the oldest vampire she had met before coming to America. She won't let any momentary fear show on her face though. If Blackstar wanted to kill her she would have done it already. In theory she was useful.

'Trust me. I am as interested to see what the Circle can get out of this as you are. I am happy to help.'