“Non-human” has quite a broad range of females to choose from, it’s so hard to pick just one with such strong women like Abaddon and Eve around who I both love. The first name I thought of was Madison, Sam’s love interest in episode 2.12 “Heart”. Madison is, by far, my favourite female werewolf, competing with Kate from Season 8, Bess, Garth’s newly-wed partner in Season 9, and Violet, a member of the werewolf family in the spin-off pilot “Bloodlines”. I thought that Madison was so sweet and caring to Sam and was incredibly brave to accept death in order to stop herself from killing people; she was one of the better monsters on the show.
That being said I think that it’s safe to say that Anna trumps everyone. Anna is most definitely my favourite female Angel (going up against many figures including Naomi and Hannah) because she was just so much more developed. I get substantially annoyed by the lack of personality in the female Angels on the show all the time and it’s hard to tell if the writers do it to show the overwhelming obedience of Angels in general or are just being slightly sexist. Most of the female Angels are either stupid or over complaint and are normally no where near developed enough.
Hannah is a personal annoyance of mine. She goes from following Castiel to Metatron to Castiel all within a couple of episodes and she doesn’t seem to question anything herself and just keeps pestering whoever she’s following at that point. Anna is much more complicated and real to me, she had her own opinions, made her own choices and had a great story. She went from being a human to being an Angel to being an assassin. She also manages to connect and create some form of relationship between both Castiel and Dean. Anna seems to understand them both and (even though she did experience human life for a while) it just shows that not all of these Angel’s have to be uncaring, arrogant beings who just follow their orders, and that they can actually have their own minds.