Water Demons

• Type: Magical Creature (Classification Category)
• Habitat: Aquatic environments such as lakes, ponds, and rivers.
• Known Examples: Grindylow, Kappa
• Ministry of Magic Classification: Varies by specific creature. For example, a Grindylow is rated XX (Harmless / Can be domesticated), while a Kappa is rated XXXX (Dangerous / Requires specialist knowledge / Wizard-killer).

“Water Demon” is a classification for a type of malevolent magical creature that dwells in water. There is no single appearance for a Water Demon; rather, the term encompasses various species with different forms that share a common habitat and aggressive temperament. Common characteristics include a dangerous nature towards humans and an aquatic or semi-aquatic existence. Known examples display varied appearances:

• Grindylows: Described as sickly green creatures with sharp little horns, long, spindly fingers used for gripping, and tentacles for propulsion.
• Kappas: Japanese water demons that resemble monkeys covered in fish scales, with a hollow on the top of their head in which they carry water (`Fantastic Beasts and Where to Find Them`).

Water Demons are generally considered dangerous to both wizards and Muggles. Their methods of attack are suited to their aquatic environment, often involving dragging victims underwater.

• Grindylows: Possess a surprisingly strong grip and will attempt to seize and drown their victims. They are vulnerable to the Revulsion Jinx, which forces them to release their hold, and they have brittle fingers that can be broken to escape their grasp.
• Kappas: Are particularly dangerous, known to feed on human blood and strangle people who enter their ponds or rivers. The strength of a Kappa is intrinsically linked to the water held in the hollow on its head. If one can trick a Kappa into bowing, the water will spill out, rendering it powerless (`Fantastic Beasts and Where to Find Them`).

The term is first used by Professor Remus Lupin during a Defence Against the Dark Arts lesson in the 1993-1994 school year, where he identifies Grindylows as Water Demons and uses one for the third-year final exam. During the Second Task of the Triwizard Tournament, Harry Potter is attacked by a swarm of Grindylows in the Black Lake. He uses the Revulsion Jinx to fend them off. Fleur Delacour is also attacked by them and forced to retire from the task. The Kappa is identified as a Japanese water demon in the textbook `Fantastic Beasts and Where to Find Them`. According to a lesson plan posted by Dolores Umbridge in the 1995-1996 school year, third-year students were meant to be reading about them, though it is unknown if this lesson took place under her supervision.

• In the `Harry Potter and the Chamber of Secrets` video game, a creature referred to as a “Water Demon” appears as a distinct enemy in a flooded section of the Hogwarts library's Restricted Section. This depiction is unique to the game and does not directly align with other known Water Demons. (video game)
• The Kappa of the Wizarding World is taken directly from Japanese folklore, where it is a well-known water spirit or yōkai with very similar characteristics.