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Ekrizdis is a minor yet pivotal antagonist in the Harry Potter universe. He was an immensely evil wizard who lived in the 15th century in medieval Britain, it is believed he was either the creator of the Dementors or that his insane experiments and torture caused the Dementors to first manifest.
Dementors are born when there is so much pain and suffer in the air that it can materialise it's self. That means that most Dementors were created during the First and Second wizarding war or in the time of Grinwald's attacks in Europe. That's why Dementors can only be destroyed by the Patronum summoning charm.
The first time we meet the Dementors is in Harry Potter and the Prisoner of Azkaban. There is Harry, happily relaxing in his carriage next to a snoozing Lupin when suddenly things go dark and, frankly, terrifying. The creature which opens the door to his cabin is not something you'd like to meet on a dark night.
Many have theorized that Dementors were a symbol for depression, and Rowling confirmed this. "That is exactly what they are," she said in a 2000 interview. "It was entirely conscious.
Get too near Dementor and every good feeling, every happy memory, will be sucked out of you.” This description of Dementors is a perfect metaphor for the symptoms of depression, which include feelings of hopelessness, anger, fatigue, a loss of interest in hobbies, and an intense sadness.
Professor Lupin explains that Harry has more dark moments in his past than most people, so there is more pain for the dementors to drudge up.
Harry's godfather Sirius Black endured 12 years in solitary confinement in Azkaban for a crime he did not commit. By focusing on his innocence he was able to survive and escape the merciless Dementors, and would later narrowly avoid the Dementors' Kiss with help from his godson.
Reproduction. Dementors breed by surrounding themselves with large amounts of a special fog which they exude. New individuals, already fully formed, will gradually congregate from the mist.
Albus Dumbledore was one who had long disapproved of the use of Dementors as guards, not only because of the inhumane treatment of the prisoners in their power, but because he foresaw the possible shift in loyalties of such Dark creatures.
Behind the scenes. It is possible that chocolate is used to ward off the effects following meeting a Dementor as it has chemicals inside it that stimulate the release of endorphins, which are chemicals produced by the body to combat stress and pain; often leading to feeling of increased happiness.
Harry describes Umbridge to Sirius Black, saying that she's vile enough to be a Death Eater, despite not being one. Umbridge is also depicted to be a prejudiced person, despising half-breeds and Muggle-born witches and wizards to the point of firing Hagrid due to his half-giant birth status.
Although Muggles could not see Dementors, they were affected in a way similar to wizards and witches, becoming depressed when near them.
It is clarified that they have genders and reproduce asexually. The Dementors refer to themselves as Mind People, due to their telepathic ability, which goes farther than the ability to suck out happy memories and allows them to communicate with humans or with each other without speaking, which they are unable to do.
Ampulex dementor is a species of cockroach wasp native to Thailand, described in 2014 by Michael Ohl of the Museum für Naturkunde in Berlin, Germany.
Speaking of joy-thieves, she might have preferred to cloak herself in pink and fill her office with fluffy kittens, but Dolores Jane Umbridge was every bit as dark as the villainous figures she liked to surround herself with. Indeed, she was the one who sent Dementors to attack Harry in Little Whinging.
They're also considered amortal instead of immortal. They don't live forever, but cannot be killed by typical means. The number of Dementors dwindle when there is more happiness in their environment. While they might not really die, they do disappear.
Muggles can still feel them, though. Its only known ability, besides the happiness drain, is the ability to perform the "Dementor's Kiss", which is the act of extracting the human soul through the mouth, leaving nothing more than a living body, without any memory, feelings, or sense of self.
The Dementor's Kiss is generally considered to be a punishment worse than death. Victims are left in what Muggles would call a Persistent Vegetative State: empty shells that are still alive but irretrievably "gone".
He rejected his family's pure-blood elitism and reverence for the Dark Arts. At Hogwarts, rather than be sorted into Slytherin like the rest of his family, Sirius was placed in Gryffindor. In contrast to his home life, Sirius greatly enjoyed life at Hogwarts, where he was inseparable from his best friend, James Potter.
The Dementor's Kiss has only been used as punishment in rare cases. Sirius Black was supposed to receive the Dementor's Kiss in 1994 after his escape from Azkaban, but he narrowly escaped from Hogwarts School of Witchcraft and Wizardry before the punishment could be administered.
His prized possession during childhood was his flying motorbike. Sirius was an animagus and was able to transform into a big black dog, (a Grim) which is an omen of death, at will. He, along with James Potter and Peter Pettigrew became Animagus to help Remus Lupin with his transformations.
Every time Harry is confronted with a Dementor, he hears the screams of his mother as she is murdered by Lord Voldemort. A horrific memory to hear... He hears this moment because Dementors feed upon happiness and cause depression and despair in anyone near them. They make people relive their worst memories.
He finds Ron and Hermione and tell them about the map. Hermione wishes Harry would turn it in, concerned that Black might know about the secret entrances on it.
Although it is not mentioned in either the film or the book, J.K. Rowling confirmed later on that, as a Dementor forces its victims to relive the worst moments of their lives, Dudley's experience causes him to see exactly who he is: cruel and rotten.