Isobel was a member of the Petrova Family and a former relative of the Saltzman Family due to her marriage with
Isobel Flemming was the biological mother of Elena. She was turned into a vampire by Damon Salvatore by her insistence. She became cold and calculating, but wished for her daughter to live a normal life. She was compelled by Klaus to find Elena, use Alaric as a host, find a vampire and werewolf for his ritual.
Elena is the the third and also the final descendant and doppelgänger of Amara, the originator of the Petrova doppelgänger bloodline. Elena's death and transition into a vampire ended the Petrova doppelgänger bloodline, as she has no descendants because she is unable to reproduce and have children.
Amara: Amara (Ancient Greek: Αμάρα, Latin: Amarantha) was born some time during 1st Century B.C.E. (100 B.C.). Her origins are from Ancient Greece and is the oldest known ancestor of the Petrova bloodline.
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.
Tatia is the first-known Petrova doppelganger, and her blood was used by Klaus' mother, Esther, to turn her children and husband, Mikaelson, into the first vampires. Following suit is Katherine Pierce, and the modern-day heroine, Elena Gilbert.
Throughout The Vampire Diaries
In the season four finale of The Vampire Diaries, Graduation, Katherine slept with Niklaus Mikaelson and conceived her daughter, Adyelya.
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.
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.
Esther uses the blood of Tatia, the original Petrova, to feed to her children. This is done because both Klaus and Elijah are in love with her. She also uses Tatia in the curse to bind Klaus's werewolf side from ever surfacing.
The Undoing: Turns Out, Jonathan Is, Indeed, the Father of Elena's Daughter - IMDb. HBO's The Undoing is basically one twist after another.
Elena Gilbert
Born in present-day Mystic Falls, Elena is the last of the Petrova doppelgangers. Her life is filled with grief and pain, as the series starts with her writing in her diary about her parents' deaths. Like Amara before her, she finds herself drawn to Stefan, Silas's doppelganger.
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.
Stefanie Salvatore is the heretic daughter of Damon Salvatore and Elena Gilbert, as well the younger twin sister of Stefan Salvatore. She is a witch from the Salvatore bloodline and a vampire, she gets her vampire side from both of her parents.
Stefanie is the witch daughter of Damon Salvatore and Elena Gilbert; the younger sister of Jenna, Grayson, and Zachary Salvatore; the older sister of Sarah Salvatore, and the older half-sister of Macaria, Johnathan, and Alatheia Mikaelson. Due to his marriage to Elena, Elijah Mikaelson is her step-father.
Damon has slept with three members of the Petrova Family: Katherine, Isobel and Elena Gilbert. Damon killed and turned her into a vampire. Damon slept with both Elena and her mom, but that doesn't seem to bother Elena (if she knows). They were both antagonists on the show at some point during the series.
Adyelya is the tribrid daughter of Niklaus Mikaelson and Katherine Pierce, the step-daughter of Markos, Leader of The Travelers—who marries her mother—and the twin sister of her younger brother by several minutes, Håkon Mikaelson, who was murdered in From a Cradle to a Grave by the witches.
She is the only biological child and the younger daughter of the original vampire, Elijah Mikaelson and the original immortal tribrid, Dianna Mikaelsson.
Dianna Monet Mikaelsson (nee Labonair) is an Original Immortal Tribrid. She is the daughter of Alaina Olsen and Cyrus Labonair. She is the wife of Elijah Mikaelson, adoptive mother of Saga Mikaelssen, and the mother of Olympia Mikaelson.
Klaus is far more powerful than Silas because he's physically the second most powerful thing walking the planet (behind the Beast of the prophecy). Silas wasn't even as strong as a vampire, he's barely stronger than a human.
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).
Nadia Petrova (Bulgarian: Надя Петрова) is a Vampire and a member of The Travellers. Nadia is also the daughter of Katherine Pierce and Markos. Nadia had spent the last 500 years searching for her mother. She is not very well accustomed to modern American culture and knows about the story of Silas, Amara and Qetsiyah.
Nadia never mentioned having children, but since Klaus killed Katherine's entire family, there was nobody else to keep the bloodline going except for Nadia's offspring. The series never addressed the plot hole.
Nadia knew Katherine wanted something. Katherine said she wants it all: her daughter, her immortality, and Stefan. "He's my one true love." Katherine decided to stay in Mystic Falls to win back Stefan.
Petrova was born in Moscow. Her father Viktor was a hammer thrower, while her mother Nadezhda Ilyina won a bronze medal at the 1976 Montreal Olympics in the 400 meter relay.