The Vampire Diaries is stuffed with every manner of supernatural creature under the sun, and despite the fact that vampires are obviously the headlining species, it's pretty clear that witches are where the true power in this fictional world is at.
Bonnie Bennett is the most prominent and powerful witch in the series, but many witches and types of witchcraft have come and gone throughout TVD's eight season run. And despite being a central aspect of the plot and mythology from the very beginning, there are undeniably some aspects to witch lore in The Vampire Diaries that still don't make any sense.
Typically any powerful magic requires some sort of sacrifice. It doesn't always have to be a literal human life being sacrificed, but giving up something in order to get something else is a pretty common element of most spells. Except, it seems like the prices vary wildly.
For instance, Qetsiyah creates the Other Side, which traps literally every supernatural spirit, with seemingly nothing more than her own power. But to create an Expression Triangle and drop the veil to the Other Side, it takes a sacrifice of 36 supernatural beings.
Another element of the witch lore in The Vampire Diaries that can be hard to suss out and seems to be completely all over the place is the power differentials between witches.
It's understandable that some bloodlines would be more powerful than others, however the fact that some witches have to kill a person in order to get their magic juju going while someone like Bonnie Bennett can create entire dimensions by accident seems too drastic of a chasm between abilities.
Qetsiyah may have been the most powerful witch who ever lived, however she was still just one person. The fact that she created an entire purgatory for supernatural beings is staggering enough, but the fact that every witch and nature spirit either couldn't or wouldn't destroy it is baffling.
Clearly they must have had enough power to unmake it, so why let it continue to exist?
Witches generally don't have a great relationship with any other supernatural species in the world. Yes, some witches cross the divide and become friends with vampires or werewolves, but there is a very common theme of witches being in the service of other supes, which doesn't make sense at all.
Based on their own beliefs, using their magical powers for the sake of unnatural creatures goes against everything that they're supposed to stand for.
What's even more confusing than the idea of witches willingly serving vampires or other supernatural creatures is the idea of them unwillingly serving them.
It's at least slightly more understandable if they're helping out a friend, but it's hard to understand how any witches could be held hostage by other supernatural beings when in theory they should possess the power to control them or at least keep them at bay.
So, once upon a time all witches lived in harmony, and then Qetsiyah went rogue, created an immortal, and the Great Divide between witches and Travelers was born. As punishment for breaking away from traditional magic, those of Qetsiyah's ilk were cursed so that they couldn't practice witchcraft.
However, the Bennett bloodline is a direct descendant of Qetsiyah, so why were they witches instead of Travelers?
Supernatural Hunters and Huntresses are gifted with plenty of useful powers and unique quirks, but one particularly interesting magical ability that the Huntress possesses is blood that is poisonous to witches.
Now, there seems to be a connection between Rayna Cruz being immune to magic and having blood that is toxic to witches, but the show never really elaborated on what that was, and there isn't enough of an explanation to truly make sense of it.
There are plenty of different types of magic that have been on display throughout the course of The Vampire Diaries, and spirits or ancestors are not the only source of magic. However, they are clearly the most common one.
And it seems that the spirits can exercise an enormous amount of control over what witches can or can't do, so it's baffling that they seem to take power away as punishments for misuse of magic instead of stopping the misuse in the first place.
It's interesting that the stated purpose of witches are to serve nature and keep it in balance, because it seems like the vast majority of witches within the series are doing far more to throw it out of balance than to bring it back into balance.
It's hard to understand why the spirits don't stop rogue witches before they actually go rogue, but it's even stranger that witches are constantly doing exactly the opposite of what they're supposed to be doing.
This really seems to be the most contradictory aspect of witches in general. They are supposed to be the servants of nature, but they are also the architects of the supernatural.
They're both supposed to keep nature in balance, but they're the ones who have created the imbalance in the first place. Their very nature seems to be in contradiction to itself.
