Katerina Petrova

Katherine Pierce Mikaelson, born Katerina Petrova (Bulgarian: Катерина Петрова) was a witch of the Traveler sub-culture and is also the second-known Petrova Doppelgänger of Amara and is a vampire.

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.

Katerina is a member of the Petrova Family. She also has ties to the Bennett Family, Labonair Family, and Mikaelson Family through Lucifer.