Katherine Pierce, born Katerina Petrova, (based on Katherine von Swartzschild from the novels) is the secondary antagonist of season two. Originally, Katerina Petrova, she was born in Bulgaria and later banished to England after having an illegitimate child. Upon meeting Klaus and Elijah, two of the original vampires, she found out that she is a Petrova Doppelganger, which means that she has to be sacrificed to release Klaus' werewolf side. She used a vampire named Trevor, who'd fallen in love with her, to escape and tricked vampire Rose into turning her, making her useless to break the curse. Katherine's escape infuriated Klaus who vowed to find her and kill her for her disobedience. She then spent 500 years running and hiding to escape his wrath. Hundreds of years later, Katherine arrived in Mystic Falls, where both Stefan Salvatore and Damon Salvatore fell in love with her. When all the vampires in Mystic Falls were discovered and brought together to be burned to death, she escaped. During her stay in Mystic Falls she had given Damon and Stefan her blood which turned them into vampires after they were shot. Damon, believing Katherine was locked up in a tomb, spent 145 years loving her and trying to find a way to free her. When he is finally able to open it, he finds out that she is not in the tomb and was alive the entire time. In the last episode of season one, Katherine returns to Mystic Falls.