Before Tyler was resurrected as a werewolf,
Katherine Pierce is from the bloodline of the original vampire Klaus Mikaelson. She was turned into a vampire by another vampire Rose in 1492.
Amara is the oldest known ancestor of the Petrova family or bloodline, being born some time during 1st Century B.C.E. (100 B.C.) in Greece. Amara was originally human but became the world's first immortal woman after she consumed the immortality elixir. Amara is assumed to be of Greek origin or descent.
Throughout The Vampire Diaries
In the season four finale of The Vampire Diaries, Graduation, Katherine slept with Niklaus Mikaelson and conceived her daughter, Adyelya.
Julie Plec confirmed that Klaus is the origin of the bloodline Stefan, Damon, Caroline and Elena are from. It is possible to unlink a vampire from their bloodline using magic. This was successfully performed on Klaus by Davina. For reasons unknown, Klaus never sired new vampires after his sireline was severed.
Ansel and Niklaus Mikaelson's Family is an unknown ancient bloodline of very powerful werewolves that goes back at least a thousand years. They are all members of the North East Atlantic Pack, that is native to America and is said to have existed since the genesis of the werewolf species.
Of all the Original siblings, Klaus was the most dominant. He was the first ever vampire and werewolf Hybrid, and the combination of two deadly races meant Klaus was unbeatable for a long time. By virtue of being the oldest vamp, he was super fast and strong, with the ability to compel even vampires to do his bidding.
Much of Elena's story revolves around her relationships with vampires Stefan Salvatore and his older brother, Damon. It is revealed that Elena is a Petrova Doppelgänger (like Katherine, Amara and Tatia), which is thus responsible for her being identical to her ancestor, Katherine Pierce (née Katerina Petrova).
Isobel was a distant descendant of Amara. Elena Gilbert (3rd Petrova Doppelgänger): Elena was born on June 22, 1992, in Mystic Falls, Virginia. She was the biological daughter of John Gilbert and Isobel Flemming, and was therefore a descendant of Katerina Petrova, to whom she bears a striking physical resemblance.
Nadia Petrova (Bulgarian: Надя Петрова)was a major recurring character of The Vampire Diaries. She was a vampire and a member of The Travelers who was Katerina Petrova's daughter, making her an ancestor of Elena Gilbert and a descendant of Amara.
Adyelya Petrova (Bulgarian: Адиела Петрова), more commonly known as Alice Pierce, is 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 Ismene. In 1490, Alice and her sister were disowned by their father.
For centuries, Klaus continued looking for ways to break the Hybrid Curse, for which he needed a Petrova doppelganger. The ritual that could undo the curse also needed a witch to channel the power of a full moon into the moonstone. Then Klaus would need to sacrifice a werewolf and a vampire.
The Curse of the Sun and the Moon was bound with Petrova blood. And the Petrova doppelganger was created to undo the spell. Thus, Klaus needed Katherine to drain her blood as a sacrifice to break the spell.
There in England, in 1492, Katherine met Klaus, who she was taken with until she found out he wanted to drain her blood to lift a vampire curse. She ran, with Trevor's help.
There are only two doppelgänger "lines" that rippled throughout history, colloquially known as the Salvatore and Petrova doppelgängers. Stefan Salvatore and Tom Avery are Silas' doppelgängers while Tatia, Katerina Petrova and Elena Gilbert are Amara's.
The Salvatore brothers were turned into vampires in 1864 by Katherine Pierce. Katherine Pierce was turned by Rose in the year 1492 in England.
Isobel was a member of the Petrova Family and a former relative of the Saltzman Family due to her marriage with Alaric. She was also a relative to the Gilbert Family, as she was Elena's biological mother.
The Undoing: Turns Out, Jonathan Is, Indeed, the Father of Elena's Daughter - IMDb. HBO's The Undoing is basically one twist after another.
However, it turned out, Katherine and Elena shared the same mother, making them half-sisters. In the series, Elena Gilbert is a distant descendant and doppelgänger of Katherine Pierce. Katherine is Elena's first kill in the books and the first vampire destroyed in the novels.
Elena is adopted and so people incorrectly assume that she is not related to Jeremy, however Elena's biological father is John Gilbert, Jeremy's biological uncle, thus making Elena and Jeremy biological cousins and therefore related.
However, Katherine refused to take away her daughter's chance at life and instead became a Passenger in Elena's body, a decision that would later result in Nadia being bitten by the hybrid Tyler Lockwood when it became clear that Nadia was up to something.
Hereditary Curse: Like Silas, as a result of Amara consuming the immortality elixir, nature created a doppelganger bloodline for Amara which would be passed down the Petrova bloodline. The Idealist: In regards to her love for Silas.
Klaus Mikaelson
However, once he became the only Original Hybrid in the world, Klaus' combined strengths turned him into the greatest supernatural creature in the entire TVD universe. It's interesting that he is both a villain and hero in this series.
The story of Sekhmet, the Egyptian feline warrior goddess associated with both plague and healing, is considered by some to be one of the oldest vampire tales. Legend holds that the sun god, Ra, sent his daughter Sekhmet down to punish humankind for their disobedience.
The age difference between the two is too minor to make much of a difference. The more decisive element is that Elena has had some combat training from Alaric and Damon. Caroline is actually Stronger, but Elena was trained to kill vampires as a human.