Katherine Pierce, born Katerina Petrova (Bulgarian: Катерина Петрова) was a witch of the Traveler sub-culture and a former main character of The Vampire Diaries. She was also the second-known Petrova Doppelgänger of Amara and a former vampire. She was the main antagonist of season one (mostly off-screen through John Gilbert's and Isobel's actions, as both were working for her in order to kill off the tomb vampires), and one of the main antagonists of season two, the second half of season four and the first half of Season Five. She was also the final antagonist of season eight. Katherine can be considered the main antagonist of the series overall due to being a major antagonist in the first, second, fourth, fifth and eighth seasons and all the antagonists that were a result of her actions. In 1490, she was disowned by her father because she brought shame upon her family after giving birth to a baby girl out of wedlock when she was seventeen. She was forced to give the baby up for adoption and then was then exiled to England. She quickly assimilated into English culture and met two nobleman brothers, Niklaus and Elijah Mikaelson. At first, she was attracted to both men, but in time, she eventually learned that she was a Petrova doppelgänger and that Klaus was planning on using her as a sacrifice in order to break the curse that bound his werewolf side. She sabotaged his plan by running away with the moonstone, which bound the curse, and then tricked Rose into feeding her vampire blood so she could turn herself into a vampire. Because Katherine was no longer human, her blood no longer was a viable component of the ritual to undo the curse. Klaus was so infuriated with Katherine's sabotage, that she was forced to live on the run for over 500 years as he hunted her down. Her activities during her first centuries as a vampire are unknown, but at some point between the 15th and 19th centuries, she took on the alias "Katherine Pierce" (an anglicized version of her birth name) and eventually met and befriended Pearl, Anna, and Emily Bennett. In the late 19th century, she traveled to Mystic Falls, where she met Stefan and Damon Salvatore, whose family hosted her at the Salvatore Estate. She later fell in love with both brothers, and subsequently fed them her blood, resulting in their eventual transitions into vampires after they were killed by their father in early autumn of 1864. When the Founder's Council found out the identities of the vampires in town, she faked her death and escaped being sealed in the tomb with the aid of George Lockwood, who helped her in exchange for the moonstone. During the twentieth century, she continued to keep tabs on Stefan while still hiding from Klaus, including two separate sightings in Chicago in the 1920s and the 1980s. In 2010, she came back to Mystic Falls with the intention of finally earning her freedom from Klaus by handing over the Petrova doppelgänger who came after her, Elena Gilbert. To sweeten the potential deal with Klaus, she killed Caroline Forbes, who had Damon's blood in her system and later transitioned into a vampire, and tricked Mason and Tyler Lockwood into triggering their werewolf curses, just so they could each also serve as the vampire and werewolf sacrifices necessary in the ritual. She even tracked down the moonstone so that she could give Klaus every component necessary to break his curse. However, when her plans ultimately fell through, she fled Mystic Falls again shortly after Klaus broke his hybrid curse on his own, knowing that he was not done punishing her for her betrayal half a millennium ago. After failing to induce Klaus' forgiveness by securing the cure and handing it over to Elijah in Season Four, Katherine managed to draw Klaus away from Mystic Falls by revealing to him in a letter that a witch in New Orleans named Jane-Anne Deveraux was plotting against him. Once Klaus and Elijah officially returned to New Orleans, Katherine moved back to Mystic Falls, confident that the Mikaelsons would be too preoccupied with their complications there to pay any attention to her. In Graduation, Katherine initiated a violent fight with Elena, believing that Elena got the life that Katherine deserved. Just as she was about to rip her descendant's heart out of her chest, Elena forced the cure down Katherine's throat, which resulted in Katherine returning to a human/Traveler for the first time in over 500 years. Following these events, she went on the run for the summer, but when she realized that her return to humanity made her vulnerable to all of the various supernatural enemies she had made over the centuries, she returned to Mystic Falls, hoping to sweet-talk Stefan and Damon into giving her their protection. However, she was forced to flee again when the immortal Silas came looking for her at the Salvatore Boarding House and tried to kill her. Silas later revealed to Damon that Katherine's blood became the cure after she had ingested it, which is why he wanted Katherine so he could cure himself and die so he could be reunited with his true love in the afterlife. She ran from him for weeks, but eventually, Damon helped Silas lure Katherine to the house and fed him her blood, which turned him back into a witch. Though Katherine should have died after Silas completely drained her of blood, Katherine's survivor instincts won out, and she managed to live through the attack. Unfortunately for Katherine, she learned shortly afterward that having the cure removed from her bloodstream had caused her body to start rapidly aging in order to compensate for the 500+ years she had been "alive" as an immortal vampire. Not ready to die, her daughter Nadia reminded her that as the daughter of a Traveler, Katherine had the magical powers necessary to become a Passenger in someone else's body. She ultimately cast the Passenger spell on her deathbed to transfer her spirit into Elena's body, with help from Nadia and a Traveler named Mia. After the gang discovered this, Stefan stabbed her with the Traveler Knife, expelling her from Elena's body, but not before Katherine made amends with a dying Nadia. Upon learning she was denied entry to the Other Side, and therefore also denied a reunion with her daughter, she was dragged by unseen forces into what is presumed to be a hell of some kind. It was revealed that Katherine was sent to Hell where she manipulated Arcadius since the minute she was sent there. She eventually returned became an ally of Kai Parker and after Cade's death and became the queen of Hell. Shortly after, she was killed by the Mystic Falls Gang after Bonnie sent hellfire back to hell while Katherine was there. Hell was destroyed and Katherine's fate remain unknown, either she was destroyed with hell or moved on and found peace. Katherine's notable ancestors include Amara, who was Silas' true love and presumably the world's first immortal woman, and Tatia, whose blood was involved in the creation of the adapted spell of immortality that was cast on the Mikaelson Family by Esther, as well the curse that bound Klaus' werewolf side. She is also the maternal ancestor of Isobel Flemming and that of Isobel's biological daughter, Elena Gilbert. She was once the romantic interest of Stefan and Damon Salvatore, as well as Mason Lockwood. Since the late 15th century, she has also been the romantic interest of Elijah, with whom she was involved in the 21st century until he effectively ended their relationship by leaving to join his half-brother, Klaus, in New Orleans. Katerina Petrova was a member of the Petrova Family.