Cruciatus Curse

The Cruciatus Curse (also known as the Torture Curse) (Crucio) is a tool of the Dark Arts and one of the three Unforgivable Curses. It is one of the most powerful and sinister spells known to wizardkind. When cast successfully, the curse inflicts intense, excruciating pain on the victim.

Considering that the curse does not physically harm the victim, it is possible that it only stimulates pain receptors. The two most well-known victims of this curse are the former Aurors Alice and Frank Longbottom, who were tortured into insanity with it by Death Eaters; Bellatrix, Rodolphus, Rabastan Lestrange, and Barty Crouch Jr.

Middle Ages
The Cruciatus Curse was invented during the early Middle Ages, by dark witches or wizards. The curse was created for torture purposes but has also been used effectively in duels. According to Barty Crouch Jr, the curse was once very popular.

After the Wizards' Council was reformed into the Ministry of Magic tighter restrictions were placed on the use of certain kinds of magic. The Cruciatus Curse was deemed by the Ministry to be dark magic, and, along with the Imperius and Killing curses, were declared "unforgivable" in 1717. The use of any of these three curses on a fellow human being would result in a life sentence in Azkaban (unless there was sufficient evidence that the caster did so under the influence of the Imperius Curse or for other defensible reasons) Many Secret Keepers in the past have been subjected to the Cruciatus and Imperius Curses in an attempt to learn the secrets they keep, but to no avail as the Keeper must reveal it willingly.

First Wizarding War
During the First Wizarding War, when Barty Crouch Snr was in charge of the Department of Magical Law Enforcement, he fought violence with violence and legalised the three Unforgivable Curses for Aurors against the Death Eaters in order to win the war. This was repealed once the war was over, as it was no longer necessary.

Shortly after Voldemort's defeat, four Death Eaters — three Lestranges: Bellatrix, Rodolphus and Rabastan; along with Barty Crouch Jr — captured the Auror Frank Longbottom and his wife Alice and tortured the two with the Cruciatus Curse for information on Voldemort's whereabouts. The repeated and prolonged usage of the curse caused the couple to become insane, the four to be captured and tried in front of the Council of Magical Law. All of them were found guilty and sentenced with life in Azkaban. This act was considered to be the most atrocious and infamous in modern history.

Between the wars
Despite the repeal of the curse's legal usage, in the 1994-1995 school year, Barty Crouch Jr, under the disguise of Alastor Moody, showed these three curses to his fourth year classes on spiders despite the Ministry's disapproval. However, since the use of the curse was illegal only on a fellow human being, the demonstration of the curses on the spider may have been within legal boundaries.

Dolores Umbridge, in a last-ditch efforts to draw information from Harry Potter, almost used the curse on him, certain in the belief that she would not be called upon to answer for it due to the only witnesses to the act being Harry and his closest friends (and the present Slytherin students would not support Harry in any way, Draco Malfoy was even looking eagerly to see it occur), and that she would be able to avoid punishment for the curse due to the political climate either way. However, she was dissuaded from using the curse by Hermione Granger, who gave Umbridge a false story in order to save Harry.

When Death Eater Bellatrix Lestrange killed Harry's godfather Sirius Black, Harry chased down Bellatrix and performed the curse on her out of rage. However, it was performed unsuccessfully as Harry was doing it out of rage and couldn't muster the will to actually cause her harm, even after Voldemort's encouragement.

Second Wizarding War
In 1997 Draco Malfoy, in a fit of rage and recklessness, attempted it on an eavesdropping Harry and later in the same year, Harry attempted to use it on Severus Snape during the Battle of the Astronomy Tower but was prevented from uttering the whole incantation due to Snape's use of Legilimency.

When Lord Voldemort took over the Ministry, the three curses were once again legalised: this time every wizard and witch had the right to use them as they please. In fact, they were practised in Hogwarts as part of the curriculum of Dark Arts class under the tutelage of Professor Amycus Carrow: students were required to practise the Cruciatus Curse on other students who earned detention, and the Carrow siblings used it to punish students as they see fit.

Alfie Campbell used this curse numerous times successfully, driving Bellatrix Lestrange to insanity and forcing many Death Eaters to surrender. He also saved Hermione Granger by using this curse.

Hermione Granger had this curse used on her by Bellatrix Lestrange during her interrogation at Malfoy Manor in March of 1998. Harry Potter managed to successfully use it on Amycus Carrow without legal consequences as well as a result of this legalisation. After Voldemort's death and the revolutionising of the Ministry under new Minister for Magic Kingsley Shacklebolt, the three curses were once again forbidden and their original penalties restored.

Harry Potter had a vision of Lord Voldemort ordering Draco Malfoy to use the curse on Thorfinn Rowle after he and Antonin Dolohov failed to capture Harry at Tottenham Court Road. Although he saw nothing of Dolohov's punishment, Narcissa Malfoy later mentioned "what he did to Rowle and Dolohov" when she was afraid to contact Voldemort.

After the wars
Everyone was forbade from using the curses until in 2020, when Minister of Magic Hermione Granger legalised the Unforgivable Curses for use by Aurors. It was then banned again following the second Battle of Hogwarts.

Nature
The pain caused by the Cruciatus Curse is described as worse than "one thousand white-hot knives, boring into the skin" and beyond what most people will ever experience. The sensation of the curse is so intense that the person under the effects wishes for unconsciousness and even death, as a means of escape. This pain can cause permanent mental injury if exposed to for prolonged time, as in the case of the aforementioned Longbottoms, who spent the rest of their lives in St Mungo's Hospital for Magical Maladies and Injuries because of the trauma the curse caused. Presumably, such permanent effects are not uncommon if the victim is exposed to a particularly intense curse for a long period of time.

As Memory Charms can be broken through torture, the Cruciatus Curse is capable of such a feat, though it requires a certain level of exposure in time and intensity to break through it. Bertha Jorkins suffered such a trial, and the end results was that both her body and mind was damaged beyond repair.

Although it is possible to use the curse on Secret Keepers to inflict pain on them, it is impossible to use it to force the secret out of them, as it must be done on the Keeper's free will.

If the curse hits an inanimate object, it may cause it to shatter instead.

Performance
To successfully perform this curse, merely uttering the incantation is not enough. The wizard or witch must possess a deep desire to cause the victim pain. For example, despite being furious with Bellatrix Lestrange for her murder of his godfather in 1996, Harry Potter was only able to cause her a brief moment of pain with the Cruciatus Curse because he used it in "righteous anger," though he was still able to knock her off of her feet with it.

Harry performed it more effectively in 1998 on Amycus Carrow, who spat in Minerva McGonagall's face. Amycus was thrown into the air and knocked unconscious. This suggests that although Harry's curse was intense, he still lacked the fundamental sadism to inflict prolonged, excruciating pain with it. On the other hand, due to Bellatrix being a witch with profound sadistic intents and little conscience, she was able to cast the curse with an almost daunting potency, and seemingly had an affinity to it. In such cases, it becomes evident that the curse's potency and results vary from caster to caster and its effects are expected to be rendered relatively ineffective when used by either those who are inexperienced or timid.

Defence
Once cast, there is no spell that can defend against the Cruciatus Curse. However, there are still evasive options available against it. The spell can be dodged by hiding behind a solid object, and a particularly strong-willed wizard can merely resist the pain until the spell is lifted, as Harry Potter refused to plea to Voldemort when being tortured by this curse and Hermione Granger managed to lie to Bellatrix Lestrange through the curse (though, as noted above, prolonged exposure can cause permanent mental damage). Another option is to interrupt the caster before they can finish speaking the incantation, as Severus Snape did to great effect against Harry Potter in 1997 by using Legilimency to anticipate the spells he would use.

Should the caster be using the Elder Wand, without winning its allegiance, to cast the curse onto its true master, the wand will refuse to inflict any pain onto its master. However, there will still be a certain level of impact that can send the body flying.

Although the main purpose of the Cruciatus Curse is to torture, it cannot be used to break through the defences set by the Fidelius Charm, as the secret must be revealed willingly and voluntarily. Also, if the victim does not possess the desired information (such as Alice and Frank Longbottom), then usage of the curse serves little to no purpose in information gathering.

Successful uses
Victim(s)---Caster(s)

Aberforth Dumbledore-Gellert Grindelwald

Numerous Death Eaters-Alfie Campbell