Who is Katherine Pierce Focus

Please watch in HD she does anything to This is for the second round of the FocusContest, hosted by Charizzaard. I had Katherine. I really liked her in the whole show. She was refreshing and as she was gone, tvd became a really boring show. I focused a bit more at the flaws she has than her badass side. Oh and i had to pitch the song a lot, otherwise it would get blocked.