Why does catherine look like elena

Isobel believed it was out of genetic curiosity. Katherine used Isobel to gain access to information about Elena, who she planned to hand over to Klaus as a peace offering for fleeing a half-century earlier. Given Isobel made it her life's work to study the supernatural, her lack of understanding of doppelgangers was surprising, particularly since she was a descendent of Amara's.

Isobel viewed Elena as nothing more than a biological curiosity. Since Elena was a Petrova descendent, that meant her mother Isobel was as well. Unfortunately, the link between Isobel and Katherine was unclear.

When Katherine's daughter Nadia Petrova, arrived in Mystic Falls during season 5, she revealed she became a vampire so that she could track down Katherine: a task that required time, skills, and resources Nadia didn't possess as a human. 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. As a naturally occurring, mystical being , Elena's blood and that of all doppelgangers contained power that, when compounded with magic, could create spells such as the ones Esther concocted to try and kill her children during season 3, or Qetsiyah's attempt to complete the Anchor swap. Her blood could also be used to undo the magic, such as the Sun and Moon Curse.

Some spells required human doppelganger blood, and others did not, although Elena's blood was more sought after commodity before she became a vampire.

Like Tatia and Katherine before her, Elena was also involved in a love triangle between two brothers, and she suffered personal tragedy resulting from her connection with the Mikaelsons. The season 4 finale of The Vampire Diaries , fans learned Elena and Katherine weren't the only doppelgangers. Stefan came face to face with Silas , who revealed that Stefan was Silas' shadow self. Just as Amara was the progenitor of the Petrova line of doppelgangers, Silas had a doppelganger bloodline of his own - the Salvatores.

Stefan's relationship with Silas was as antagonistic as Elena's was with Katherine. Season 5 established a strong connection between male and female doppelgangers: they were fated to find each other and fall in love.

Qetsiyah told Damon that during the centuries she was trapped on the Other Side, she watched "destiny trying to get the doppelgangers together forever. The idea that male and female doppelgangers were meant to be together was debunked by Markos, the leader of the Travelers.

He revealed they were drawn together because of magic. Season 5 focused heavily on the consequences of the Amara-Qetsiyah-Silas love triangle. Nature created doppelgangers to restore the balance disrupted by Qetsiyah's and Silas' immortality spell, and witches parlayed the existence of doppelgangers into a way to punish the Travelers for Silas' and Qetsiyah's actions. While the series devoted multiple seasons to exploring the complexity of the Petrova doppelgangers as individuals and their relationships with each other, revealing Stefan to be a doppelganger felt like an afterthought.

Being part of a doppelganger bloodline didn't impact him in the same way it did the Petrova doppelgangers. First and foremost, Stefan was always a vampire - a "Ripper. Still, neither he nor Damon understands the link between the woman they used to love and the woman they currently love. Being a descendant is one thing, but being exact replicas of one another adds another layer to the mysterious connection between Elena and Katherine.

When Elena, Alaric, and Damon go to Duke to look through Isobel's research in season 2's "Bad Moon Rising," Isobel's research assistant defines a doppelganger as a "living, breathing double of oneself. It's Katherine who finally reveals how she and Elena are connected during season 2's "Katerina. Katherine's father gives the baby away. Presumably, this child grows up and keeps the Petrova bloodline going after Klaus murders Katherine's family in This solves the mystery of Katherine and Elena's ancestral connection, but not what a Petrova doppelganger is and why Klaus needs one so badly.

Katherine's explanation about the purpose of the doppelganger isn't entirely incorrect. The doppelganger blood of her and Elena's ancestor Tatia is the binding agent Esther uses to turn her children into vampires and to suppress Klaus' werewolf side, but doppelgangers serve a much larger purpose.

They are the magical byproduct of Qetsiyah and Silas' immortality spell. Bonnie is clearly affected by the similarities between them. After Katherine rejects Damon, he turns up drunk at Elena's, only to be rejected by her as well. Damon gives Elena a book which may contain more information about Katherine. Elena goes to the Salvatore Boarding House to find Stefan, who was holding Katherine prisoner in an attempt to get the truth from her, but came face to face with Katherine for the first time instead.

Elena asked her how they looked alike, but Katherine said she was asking the wrong questions. Katherine examined Elena just as Stefan arrived and she disappeared. Elena bribed Katherine with blood to tell her her story. Katherine said Elena had the "Petrova fire". Katherine told Elena her story: she was supposed to be sacrificed in but escaped and became a vampire instead. She had a baby girl out of wedlock that carried on the bloodline , but was kept secret and given away.

When she was sent to England she was found by Klaus who tried to kill her in the sacrifice. Trevor assisted her while Rose wanted to turn her in but Katherine tricked Rose into feeding her her blood as Katherine then killed herself, becoming a vampire. After Elena returned home she told Stefan she was not only afraid for herself, but for the people around her as it was her fault that everyone would be hurt or killed.

She seemed to believe everything that Katherine told her. Katherine pretended to be Elena again and fooled Stefan and Damon, pleased she was improving in her impersonations. Katherine insisted she wanted to help and posed as Elena when Jonas came to kill her. Elena refused to thank Katherine, angering her. Elena also became suspicious of her. Later, Katherine takes Elena and switches clothes with her in order to get her to Isobel, who would turn her in to Klaus. Isobel had lied to Katherine about Klaus wanting Elena in exchange for Katherine's freedom when, really, he wanted Katherine.

Stefan saw through her facade when she pretended to be Elena again. Katerine doesn't seem to dislike Elena as she once did, instead trying to help Stefan.

She impersonated Elena to help with the plan to kill Klaus. By this point, they seem to have reached a mutual alliance. Katherine appears to Elena in a hallucination after she kills Connor , tormenting her. Katherine tells Elena she's just like her and that she should kill herself. She proceeds to tell Elena that now that she's a vampire , Stefan is going to hate her.

This sends Elena over the edge and she attacks Stefan when he tries to help her. Katherine, along with Connor and Miranda , pushes Elena to try and kill herself in the daylight but Damon saves her by pushing her underwater when the sun comes up. Elena and Katherine have a run in on the island when Elena is looking for Bonnie and Jeremy.

Elena's horrified to discover that Katherine is there. Katherine attacks Elena and tricks Jeremy into believing she's Elena. She uses Jeremy as a sacrifice to get the cure from Silas. She bites Jeremy and uses his blood to wake Silas, killing Jeremy. She then fled with the cure. Elijah spoke on the phone to Stefan, threatening to harm Elena if he harmed Katherine.

He then spoke to Elena and told her that he was hoping there was still a part of Katerina inside of Katherine, and he was trying to get through to her. Elijah seemed sorry that Elena had lost her humanity and, when he asked why, she revealed that Katherine had killed Jeremy. They flirted until Elena revealed how different she is by revealing she burned his letter and Katherine showed up, snapping Elena's neck.

Elijah confronted Katherine over her lies, choosing to believe Elena over Katherine, and she begged him not to believe Elena. Elijah seemed mad that Katherine had snapped Elena's neck and Katherine was hurt. Stefan and Damon decided to get Katherine to torture Elena, as Elena would not know if Katherine would kill her or not and it would provoke fear. Katherine visits Elena in her cell and asks her what she told Elijah.

Elena called her a self enigmatic bitch and insulted her. Katherine then threatens to rip out her heart, putting her back in the cell, but leaving it unlocked, telling her to try surviving on her own without everyone in love with her.

After Elena regains her humanity, she says she's going to kill Katherine. Katherine was working with Bonnie when she hears someone coming and she goes to check. Elena ambushes her, kicks her around, and almost kills her before Stefan stops her, telling her that Katherine's linked to Bonnie.

Elena's hurt, believing Stefan's still in love with Katherine. Elena has a dream about Stefan, after which time Katherine informed her that she had been having the same dreams, too. Katherine tagged along with Elena and Damon to find Stefan, and taunted Elena about being too interested in her relationship with Damon to even think about what her dreams meant.

Later, Elena helps Katherine escape from Nadia in the bar when she came to capture her on Silas' orders. Katherine was running in the woods when Elena caught up to her. Katherine mentioned how she was glad to see Elena. She then asked why Elena didn't kill her after giving her the cure, but Elena replied that she is not like Katherine, and also conceded that the fact that living as a human was a fate worse than death for Katherine was just a "happy accident.

Katherine told Tessa she didn't care about Elena getting her best friend back, and asked for Tessa help to stop the accelerated aging that began after she ingested the cure in exchange for her blood for the spell.

Later Tessa began the spell, and Katherine commented on Elena showing off when she sliced her hand for the blood sacrifice, as her vampire nature made it much easier than it was for Katherine, being human. Later, Amara went missing, and they concluded that she was in the woods as an offering to Silas. In Years of Solitude , before the episode ended, Katherine's last visitor was Elena, who forgave Katherine for everything that she had done to her.

In typical Katherine fashion, she made no apologies, but she did thank Elena for her forgiveness. She then asked Elena to be the one to give her last injection of sedatives, citing the symmetry of the situation. However, unbeknownst to Elena, Katherine took advantage of Elena's distraction with the medication to take possession of Elena's body, using the Passenger spell Mia and Nadia taught her and using her Traveler heritage.

Shortly afterward, Katherine's original body died, but her spirit lived on in Elena. In The Devil Inside , Katherine was still in control of Elena's body, but Elena was using all of her strength to fight against the possession, and frequently gained back temporary control until Nadia could call Katherine forth again. Katherine, knowing that Elena had inherited her survival instincts, changed the password on Elena's phone so she couldn't use it to call for help when she managed to regain control.

Elena did manage to get control back in the middle of Mia casting the spell to give Katherine permanent control over her body, but Nadia was able to heal Mia enough to allow her to complete the spell anyway.

Elena had just managed to jump into Damon's open arms when the spell was activated, causing Elena to see flashes of all of Katherine's memories before Katherine's spirit completely dominated Elena's.

Katherine then, having complete autonomy, pretended to be Elena and informed Damon that she didn't want to get back together with him, citing the way Damon treated Katherine before her "death" as the reason why she couldn't be with him.