Keeping secrets on The Vampire Diaries was a common occurrence. At one point or another, everyone had something to hide. In the early episodes, the supernatural itself was an interestingly kept secret. The Council and founding families knew vampires existed but had no idea who could be a vampire in their town. The Council didn't have all the correct information about vampires, which certainly helped some stay under the radar.

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But, as the series progressed, there were even more secrets that came to light. Things Stefan and Damon had never mentioned before become major events in their lives. Bonnie's death becomes something she and Jeremy try to keep from everyone until they can't anymore. Some secrets were major game-changers for the characters and overall storyline.

Stefan And Damon: They Are Vampires

Vampire Diaries Damon And Stefan Season 7

This is one of the biggest secrets Stefan keeps from Elena when they meet. As their time grows together, Elena notices suspicious things about Stefan, such as how quickly his wounds heal even when Elena knows he was injured or how older strangers recognize Stefan from having seen him decades before.

Elena decides to dig into the past and finds out that Stefan and Damon are vampires. While Damon keeps this secret from Elena as well, he mainly hides it from Liz and the council, choosing to pretend to be human in order to learn what they are up to and how much they know.

Elena: The Supernatural Exists

Elena looks between Damon and Stefan in The Vampire Diaries.

More often than not, Elena keeps or learns other people's secrets rather than having any for herself. In that respect, one of Elena's biggest secrets is that the supernatural does exist. Elena keeps quiet about Stefan and Damon being vampires to Jenna, as well as not telling Jenna the truth about Isobel being her birth mother and Alaric's ex-wife.

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Jenna believed Isobel was dead and was betrayed to learn that Elena knew Isobel was still around. Still, Elena did not tell Jenna that Isobel was actually a vampire.

Katherine: Her History With Klaus

Katherine Pierce and Klaus Mikaelson looking at each other

Katherine's actions when she first appears are unpredictable and confusing. She is obviously after something, later known to be the moonstone, but her motives are not understood at first. It isn't until Katherine tells the whole truth to Elena that it starts to add up. Katherine had decided against helping Klaus with the ritual because she knew it would mean her death. But, Katherine still wanted to survive.

Thus, she turned herself into a vampire, and by being dead, Katherine was no longer useful to Klaus. But, he still made a point to get revenge by slaughtering her family. Katherine had spent 500 years on the run by the time she meets Elena.

Stefan: His True Reaction To Human Blood

Ripper Stefan with blood on his lips in The Vampire Diaries

At first, Stefan makes it sound like he does not drink human blood because it is morally wrong. When Stefan helps Vicki, he tries to get her on animal blood early and explains that he has not had human blood in a long time. But, Stefan heavily omits the truth about why he changed to animal blood.

Although Stefan may believe it might be wrong to drink directly from the vein, Stefan's true reason for drinking animal blood is that he turns into a ripper on human blood. Stefan is addicted to human blood, and once he starts, it is almost impossible to stop. To prevent himself from hurting anyone, Stefan and Lexi put him on an animal diet.

Klaus: He Killed His Mother (The First Time)

Klaus and Rebekah in the Middle Ages in The Vampire Diaries

Although The Originals suggests Elijah had learned the truth about his mother's death from Aurora centuries before, Rebekah was completely unaware of it until arriving in Mystic Falls. Klaus had kept that secret and said that Mikael had killed Esther. Rebekah is heartbroken when she learns the truth.

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Yet, when Esther returns to life, her entire goal is to strip her children of their immortality and kill them all for their sins. At which point, Klaus feels less guilt over her second death.

Damon: Being An Augustine Vampire

Vampire Diaries Damon as Augustine

Damon being tortured alongside Enzo for years as an Augustine Vampire was something he left out during reunions with Stefan after his escape.

Damon never told anyone until the past caught up with him. His relationship with Enzo and his revenge plan to kill the family that tortured him, leaving only one of each generation alive forever, remained a secret until Damon and Elena were captured together.

Bonnie And Jeremy: Bonnie's Death

Bonnie talking to Jeremy on school bench in The Vampire Diaries

Jeremy and Bonnie successfully tricked Elena, Caroline, and Matt into believing that Bonnie was alive and had simply been out of town throughout the summer where she was absent.  Jeremy was the only one who could talk to Bonnie while she was on the Other Side, and Bonnie had begged Jeremy not to tell anyone she was actually dead.

However, their game could not go on forever. When the group needed Bonnie, Jeremy had to tell Damon the truth, and everyone was devastated to mourn Bonnie and realize that she had been gone for months. Through Jeremy, Bonnie gives each of her friends a message.

Stefan Killed Enzo (The First Time)

Stefan and Enzo staring at each other in TVD

Enzo was not making himself someone Stefan liked having around his brother. When things came to a head between Enzo and Stefan as they were fighting, it looked like Stefan was in a position to end Enzo's life. But, rather than Stefan killing Enzo, Enzo took advantage of Stefan's hand holding his heart and backed up, letting Stefan's hand grasp Enzo's heart and pull it out.

Stefan considered that his fault and he told Elena about what happened. While Stefan, Elena, Damon, and Caroline were hiding out together, Caroline and Damon started to get suspicious about what Stefan and Elena were keeping to themselves.

Klaus And Elijah: The Sun And Moon Curse Was Fake

The Originals Ashes To Ashes Elijah and Klaus

To get vampires and werewolves searching for the Doppelgänger, Klaus and Elijah created a fake curse, the Sun And Moon Curse, that would allow vampires to walk during the day and give werewolves power over their transformation. Their idea worked, and over the centuries, their false story gained traction, and people began to believe this was a way out of their situation.

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However, others knew better. Elijah explains to Elena that the curse she believes to be real is a fraud and had been invented for the sake of getting others to help find the Petrova Doppelgänger. The true curse Klaus wanted to break was a werewolf bind placed on himself.

Stefan: Sarah Salvatore Survived

Stefan squinting and looking serious in The Vampire Diaries

One of Stefan's biggest secrets doesn't come to light until Enzo starts getting a little too curious about Stefan's lies. In 1994, Damon had slaughtered innocent people staying at the Salvatore Boarding House, including who he thought to be a pregnant woman and her baby.

Except Stefan brought the woman to the hospital and stayed to learn the baby survived. He made sure she was adopted by a nice family and had no interest in vampires. Sarah Salvatore grew up as Sarah Nelson. Unfortunately, Damon learns Stefan's big secret moments before he kills her.

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