The Unforgivable Curses of Harry Potter are some pretty intimidating magical spells. They're the most dangerous spells in the series, and illegal for most of it — until the Ministry of Magic becomes corrupt, but that's another story.
They come in three forms: the Imperius, the Cruciatus, and the killing curses. Each of them comes with an incantation and directions, and none ar easy to perform. They take a particularly skilled (and hateful) magical person.
But we still have some questions about them that just don't make sense, and J.K. Rowling hasn't yet provided answers.
10 THE LIGHT COLORS
Each of the spells has a color of light associated with it. For the killing curse, there is green. For the Cruciatus curse, there is red. For the Imperius curse, there is blue.
It seems unlikely that each of these was randomly chosen and that they probably hold some significance, but we can't quite out what. The Cruciatus curse being red makes the most sense, because red is the color of pain and anger but... green and blue? Surely the killing curse should be blue, as it's the coldest color?
9 WHAT CAUSES THE CRUCIATUS' PAIN?
The Cruciatus curse is, in many ways, the worst of the three, because it can torture a person into insanity which is debatably worse than a painless death from the killing curse. When Harry experienced it from Voldemort in Goblet of Fire, we get a detailed description of the agony for the first time: how he screamed, how his eyes rolled back in his head, how he forgot where he was and only knew he would rather die than endure such pain.
But... what's actually happening to the body when undergoing such pain? Are the pain nerves being set alight, or is the pain totally imagined? We're morbidly interested in more details about exactly how this curse works. It's dark, but it's fascinating.
8 HOW CAN MAGIC NOT BLOCK THEM BUT A GRAVESTONE CAN?
It's stressed throughout the series that the Unforgivable curses are utterly unblockable. No shield charm can block them, no magic can withstand them. Once they're cast, they'll go through any enchantment.
What's odd about this is that Harry dodges one by using a gravestone to block it when Voldemort fires it. Is a gravestone stronger than a magical spell, or is it something about how physical the stone is that stops the curse where magic can't?
7 HOW DOES THE IMPERIUS CONTROL ACTUALLY WORK?
We don't really get a detailed description of how the Imperius curse works, which means it doesn't make that much sense to us. The description is more detailed when Harry is on the receiving end of it — otherwise, we don't really know how it's used, what emotions are tied to actually casting it, etc. It'd be interesting to know more of this because it's the curse that makes the least sense to us, based on lack of information alone.
6 SO HOW DOES FIGHTING IT WORK?
Strength of character and self-assurance are apparently the only things that stand a chance against the dreaded Imperius curse, but there's a lot about that that... doesn't quite make sense. It seems odd that strength of character is more powerful than a shield charm but then again, isn't that what this series is about? How love and inner strength are more powerful than magic?
Still, in this case, we have to question the logic just a little bit.
5 HOW DO YOU CAST AVADA KEDAVRA?
It's emphasized that you need to really want to cause pain to cast the Cruciatus curse, but the killing curse is never explained on the same level so we don't have the same amount of logical sense about it. Presumably, the person needs to truly want the other person dead, but as it seems to be the most powerful of the curses (and some might say, the worst), maybe it requires more?
4 BUT... LOVE CAN BLOCK IT?
Love being able to block the killing curse is something we might never be able to understand purely because it... doesn't make much sense. The sacrifice of love, it's said, is what blocks the curse but then, is love a form of magic? Or is the emotion itself simply more powerful than any magic could hope to be? This is kind of explained away but not very thoroughly, and this part of the lore left us with more questions and answers.
3 WHO EVEN MADE THESE CURSES?
You know what doesn't make sense? Who created these curses and why? Who decided we needed a torture, control, and killing curse? And were they all created by the same person, or were there three different inventors of these spells and they came together to be called the Unforgivable curses later?
2 HOW DID AURORS USE THEM ETHICALLY?
Once upon a time, Bartemius Crouch Sr. was head of the department of magical law enforcement in the Ministry of Magic. He authorized the use of Unforgivables against criminal targets by Aurors. The problem with this? If the curses require someone to be casting them who truly wants to cause pain, who truly is feeling sadistic in that moment, how could Aurors ever ethically use them? Is it possible? Or were they simply corrupt and Barty Sr. didn't care as long as dark wizards were being captured?
1 HOW DID HARRY CAST THE CRUCIATUS CURSE ON CARROW?
On that same token, Harry casts the Cruciatus curse successfully on a Death Eater named Carrow after he insults Minerva McGonagall by spitting on her.
It's a sign the Chosen One isn't as pure and good as we'd like to believe, but it doesn't make much sense considering he couldn't even cast it on Bellatrix Lestrange after she killed his godfather, Sirius Black. But a Death Eater spitting on one of his favorite teachers was enough to invoke such hatred? Hmm... Seems like there may be a bit of a continuity error there!