Throughout the course of The Vampire Diaries, the show had a lot of different big bad villains, but the biggest and baddest of them all has got to be the literal queen of hell, Katherine Pierce. This doppelganger certainly learned how to set herself apart from the crowd, and her willingness and ability to do whatever it took to ensure her own survival or chase her own happiness was totally unparalleled.
Katherine definitely had occasional moments of softness, but for the most part, she relished in her ability to be the worst, scariest vampire in all of the world. Even Klaus Mikaelson, the man who spent half a millennium torturing her, had to at least respect her hustle. But throughout her five hundred years of life, Katherine did an incalculable number of absolutely awful things. It's hard to narrow down the worst of the worst, but here are the ten worst things Katherine Pierce ever did.
Letting Humanity-Free Elena Out
Katherine Pierce has always had a very contentious relationship with Elena Gilbert, and she's pretty good at finding new and inventive ways to torment the latest doppelganger. However, letting Elena go when she had her humanity switch flipped was probably the cruelest thing that Katherine could have done to her.
Elena can endure a lot of suffering and pain, but Katherine rightfully understood that the guilt of doing horrendous things would probably hurt Elena more than anything. So after trading a few barbs with the newly mean Elena, Katherine decided to set her loose on society and see what kind of awful things she'd get up to.
Taking Elena's Body
Katherine is a character who obviously wants to survive no matter what the cost, so it is not at all surprising that when it seemed like she was finally going to bite the dust for good she found a way to keep going just a little bit longer. However, body-jacking someone is the creepiest, most unsettling way to do that.
And even putting aside the fact that she was literally stealing Elena's body, she also seemed to want to steal Elena's life. The fact that she was going to stay with Elena's friends and family and just pretend to be her for as long as it entertained her really adds another layer to the creep factor.
Letting The Tomb Vampires Take The Fall For Her
When someone's life mantra is "better you die than I" it's not very surprising that Katherine consistently left other people holding the bag while she saved her own behind. But when it comes to the vampires who were trapped in the Mystic Falls tomb, Katherine's cruelty seemed to go really above and beyond even the average evil behavior.
Once things started to hit the fan in Mystic Falls things quickly devolved into chaos, and all of the tomb vampires wound up getting caught, while Katherine once again got away. And obviously Katherine could have at least done something to help her supposed friends afterward, but she was content to let them rot.
Escaping Klaus
You know, if you discover that some ancient vampire is planning on using you as his ritual sacrifice, it's natural to decide that now is a good time to get out of dodge. However, Katherine's plan for escaping Klaus was straight-up terrible.
She killed herself so she could turn into a vampire, even though in theory she could have just drunk vampire blood before the ritual and gotten the same result without triggering Klaus to seek revenge on her and everyone else involved in the situation. And of course anyone who helped her was royally screwed by her move, but she once again was content to leave them facing the consequences while she escaped.
Forcing Mason To Turn
We all know that Katherine Pierce is a bad person, however her decision to force Mason Lockwood to turn into a werewolf seems really unnecessarily cruel. She's a very skilled manipulator, so she could have easily just seduced him to get the moonstone without him being the wiser about anything supernatural.
And there are more than a few werewolves out in the world, so if she was looking to serve one up for Klaus and his sacrifice then she could have found one. But instead, she subjected Mason to a lot of torture and got an innocent man killed because it was slightly more convenient.
Forcing Tyler To Turn
So once Mason Lockwood was out of the picture it would seem that Katherine needed another werewolf on deck. Or rather, she didn't really need it, she just assumed that handing Klaus all of the keys to the ritual would make him more likely to forgive her and finally stop hunting her.
Once again, instead of just going out to find another werewolf somewhere she decides to force Tyler Lockwood to turn. She has no reason to care about Tyler or about the innocent bystander that she forces him to kill, but it just goes to show how casually Katherine murders people, even if she doesn't have to.
Leaving Stefan And Damon Behind
Katherine makes a lot of bold claims about the fact that she actually did love Stefan and Damon, but her behavior after they became vampires certainly wouldn't indicate that. She was continually dosing Stefan and Damon with her blood, presumably because she was planning on making them vampires at some point, but once the metaphorical and literal trigger had been pulled she abandoned them and let them believe she was trapped in the tomb.
Katherine certainly likes to travel light, but it's strange that she didn't even bother bringing them along on the run with her if she genuinely loved them as she claimed to.
Getting Stefan And Damon Killed
So leaving Stefan and Damon behind was one thing, but pretty much getting them killed is quite another. Damon was at least a willing participant in his relationship with Katherine, but Stefan had to be compelled to stick around once he figured out what Katherine really was.
And while Damon and Stefan both came to Katherine's defense when their father became a threat to her, it literally cost them their lives. Plus, even though Damon understood what Katherine was and was still her ride or die, she plainly lied to Stefan and Damon about the lives they would lead with her once they became vampires. They likely wouldn't have done anything they did if they knew the truth.
Killing Jeremy
Katherine obviously has a nasty habit of killing people just because it's remotely convenient for her, and her natural cruel streak seems to be multiplied by about a hundred when it comes to Elena Gilbert. However, killing Jeremy on the quest for Silas was a completely pointless and unnecessary move.
While Silas was really the one who killed Jeremy for good, all he really needed was a little blood. If Katherine had just left it at Jeremy's slit wrist instead of ripping open his neck to get things moving a little faster then at least Jeremy could have had a fighting chance at survival.
Killing Caroline
When Katherine finally returned to Mystic Falls she obviously wanted the entire Mystic Falls gang to constantly be on the defense and always terrified of what she was going to do next. But her biggest and boldest move was undoubtedly turning Caroline into a vampire.
Caroline managed to actually flourish after her transition, but that was a really rocky road and she nearly died dozens of times because of it. Caroline was just a pawn in her game against Elena and the Salvatore brothers, but it's hard to deny that Katherine made no other move that had a greater impact on everything than killing Caroline.