Dementor

A Dementor is a non-being and one of the foulest creatures to inhabit the wizarding world. Described as “soulless and evil,” they feed on positive human emotions, draining happiness and hope from their victims and the very air around them. Their presence creates an intense, bone-chilling cold. Where large groups of Dementors congregate, such as at the Azkaban fortress, they can generate a perpetual fog and a pervasive atmosphere of misery. Physically, a Dementor is a towering, human-shaped figure cloaked entirely in a dark, hooded robe that conceals its face. What little can be seen of their bodies appears dead and decayed, like something long-drowned. Their visible hands are greyish, slimy-looking, and scabbed. A Dementor glides silently over the ground rather than walking, and it possesses a rattling, sucking breath. Beneath its hood lies a formless, skull-like face with no visible eyes. Its most terrifying feature is a great, dark hole where a mouth should be, used for performing the Dementor's Kiss.

Dementors possess two primary and devastating abilities used to prey on humanoids.

• Aura of Despair: A Dementor's mere presence drains all happiness from its vicinity. Anyone who comes too close is forced to relive their worst memories, sinking into a state of profound depression and hopelessness. This passive effect is their primary method of feeding on positive emotions.
• The Dementor's Kiss: This is a Dementor's most fearsome attack. It latches its mouth onto a victim's and sucks out their soul, leaving them as a living but empty shell. The victim is left without self, memories, or consciousness—an existence considered by many to be worse than death. The Kiss is irreversible and was historically used as the highest punishment by the Ministry of Magic. Barty Crouch Jr. suffered this fate after his exposure at Hogwarts.

While formidable, Dementors are not invincible and have specific weaknesses that can be exploited.

• Patronus Charm: The Expecto Patronum charm is the only known spell effective against Dementors. It conjures a Patronus, a magical guardian of concentrated happiness and hope, which a Dementor cannot feed on. A corporeal Patronus can actively charge and drive Dementors away, while an incorporeal one acts as a temporary shield.
• Chocolate: Consuming chocolate is an effective first-aid measure after a minor Dementor encounter. It does not repel a Dementor but helps counteract the lingering feelings of cold and despair, allowing the victim to recover more quickly. Remus Lupin provided Harry Potter with chocolate on the Hogwarts Express, and Madam Pomfrey regularly prescribed it for this purpose.
• Blindness: Dementors are blind and sense their victims by feeding on their emotions. This makes them unable to easily distinguish between one human and another, and they can be confused by less complex emotional states. Sirius Black famously used this weakness to escape Azkaban by transforming into his dog Animagus form; the Dementors could not detect his less complex canine emotions, allowing him to slip past them.

Dementors were first discovered infesting the island fortress of Azkaban, which was originally the home of the dark wizard Ekrizdis. (Pottermore) When the Ministry of Magic took control of the island, they chose to contain the Dementors there and utilize them as guards for the new wizarding prison, a decision that Albus Dumbledore vocally opposed for many years. For centuries, the Dementors served the Ministry of Magic in this capacity, feeding on the emotions of the prisoners. However, their allegiance was only a matter of convenience. During the Second Wizarding War, they abandoned their posts at Azkaban to join Lord Voldemort, as he could provide them with a greater scope of fear and despair to feed upon. Under Voldemort's command, they participated in several key events, including the attack on Harry Potter and Dudley Dursley in Little Whinging (an attack secretly ordered by Dolores Umbridge) and the Battle of Hogwarts. Following Voldemort's final defeat, the new Minister for Magic, Kingsley Shacklebolt, officially ended the use of Dementors as the guards of Azkaban, recognizing them as untrustworthy and inhumane creatures. (J.K. Rowling interview)

The name “Dementor” is derived from the English word dement, which means “to make someone insane.” This, in turn, comes from the Latin prefix de- (“away from”) and mens (“the mind”), aptly describing the creature's effect on its victims.

• J.K. Rowling has stated in interviews that the concept of the Dementors was born from her own personal experience with depression before she became a successful author. The feeling of cold, emptiness, and the inability to feel happiness were translated into the creature's magical properties. (J.K. Rowling interview)
• In the film adaptations, Dementors are depicted as more skeletal, wraith-like beings that can fly through the air, a slight departure from the gliding movement described in the books. (film)