In 1899, it was mentioned that the dark wizard, Gellert Grindelwald, sought to create an army of Inferi, and believed that the Resurrection Stone could grant him such powers. It is unknown as to whether he succeeded, though his conception of the stone's abilities was in fact incorrect, as it brings back souls from the realm of the dead as more-than-ghost but less-than-alive state, not as a living body.
First Wizarding War (1970 -1981)
During the First Wizarding War, Voldemort was known to have created an army of Inferi from the large number of people he murdered. He placed such an army within the lake of Salazar Slytherin's Locket's hiding place. The Inferi in question were mostly vagrant, homeless Muggles murdered by Voldemort, but some of them were the earthly remains of wizards and witches who "disappeared" without explanation. In 1979, when Regulus Black attempted to destroy the said Horcrux, he succumbed to the Drink of Despair's effects and tried to take a drink of water from the lake, only to trigger the Inferi and was killed by them. Kreacher, his house elf, managed to make it out of the cave with the locket.
Second Wizarding War (1995 -1998)
Not exactly counted as a real encounter, but worth mentioning: Mundungus Fletcher was arrested and put into Azkaban because he disguised himself as an Inferius after being caught during an attempted burglary.
Hunting for Horcruxes
In 1997, Harry Potter and Albus Dumbledore encountered the very same army of Inferi as Regulus in their attempt to destroy Voldemort's locket Horcrux. At first, they remained inert as the two sailed in the boat towards the central island. However, when Dumbledore suffered from the Drink of Despair's thirst-inducing effects, Harry had to take some water from the lake, triggering the Inferi, who nearly dragged Harry to the depths of the lake to drown. Dumbledore successfully repelled them by conjuring a ring of fire, big enough to surround both Harry and himself. Once all the Inferi returned into the lake, they did not resurface when Dumbledore's ring of fire faltered.
2014 Quidditch World Cup
In 2014, rumours that the Haiti was using Inferi to intimidate other teams were dismissed by the ICWQC as untrue. However, the rumours proved true when Inferi attacked crowds in the opening ceremony of the 2014 Quidditch World Cup, leading to 300 casualties.
The Inferi are gaunt, skeletal beings that closely resemble zombies. Being human corpses, they have individual appearances based on the humans they were created from. For example, one Inferius may have dull teeth, while another may have sharp teeth.
Inferi have no free will, and cannot think for themselves; their purpose is merely to serve as puppets of the Dark Wizard who reanimated them. The spells required to reanimate dead bodies are much more complex than those used to make inanimate objects fly. As no spell can bring back the dead, the Inferi are not alive, just corpse puppets. Despite this, they can apparently speak.
Due to their status as being unfeeling dead, the Inferi are immune to bodily damages such as slashing, and have great physical strength, enough to kill a human or drag them away. Due to their superior strength and surprising speed, they are especially dangerous en masse.
Defence against Inferi
Because Inferi are creatures of the dark, they dislike light and heat (no spell has been found to render dead flesh impervious to burning). The most effective spell against them is therefore a fire-summoning spell, such as Firestorm. Because of this, the Inferi are enchanted by their master to avoid flames. Other spells might work against a few Inferi, but might not be useful against a whole army of them. It must be noted that Inferi are resistant to most spells: they cannot feel pain, and thus are unaffected by many attacks whose main effect is pain such as the Cruciatus Curse. This is evident when Harry Potter attempts to use the dark spell Sectumsempra on the Inferi in the Crystal Cave, as they have no blood to spill.
Inferius is a tampered form of the Latin word for "underneath; below", Inferus, but with an obvious connotation of being 'lesser' than a living human. Meanwhile, Inferi means "the dead; underworld". J. K. Rowling has changed this real Latin words to form these creatures. 
Behind the scenes
- According to W.O.M.B.A.T., Inferi may have the ability to speak.
- Inferi may have been briefly referred to by Voldemort in the Little Hangleton Graveyard as part of an "army of creatures whom all fear".
- Inferi may be incredibly strong as a picture in Snape's Defence Against the Dark Arts class shows a bloody mass on the floor, attributing to a person provoking the anger of an Inferius. Alternatively, this could be attributed to their viciousness and implacability.
- Zombies are different from Inferi, although they have much in common. It seems that zombies are naturally formed, while Inferi are artificially created. J. K. Rowling decided against naming the Inferi zombies because zombies are not part of British folklore. Also, one tradition has the sorcerer using his soul, or part of it, to sustain himself, which she decided conflicted with her Horcrux story.
- In first part video game adaptation of Harry Potter and the Deathly Hallows, Inferi appear again, despite them not being in the mainstream storyline.
- Harry Potter and the Half-Blood Prince (First appearance)
- Harry Potter and the Half-Blood Prince (film)
- Harry Potter and the Half-Blood Prince (video game)
- Harry Potter and the Deathly Hallows (Mentioned only)
- Harry Potter and the Deathly Hallows: Part 1 (video game)
- The Tales of Beedle the Bard (real)
- Harry Potter: A Pop-Up Book
- LEGO Harry Potter: Years 5-7
- Harry Potter for Kinect
- Harry Potter: The Creature Vault
Notes and references
- ↑ The Tales of Beedle the Bard
- ↑ 2.0 2.1 Harry Potter and the Deathly Hallows
- ↑ 3.0 3.1 3.2 3.3 Pottermore - New from J.K. Rowling: Inferi
- ↑ 4.0 4.1 4.2 4.3 Harry Potter and the Half-Blood Prince
- ↑ The fact that Inferi are able of speech is hinted at in the second W.O.M.B.A.T. featured in J. K. Rowling's Official Site. Question 1 (Part One - Magical Beings) is "Which of the following statements is TRUE?", and one of the possible answers is "Inferi cannot speak". As one of the other answers is known for certain to be true ("Hags eat small children" — the Chocolate Frog Cards reveal that Babayaga fed on children for breakfast; and the Daily Prophet Newsletters say that Regulus Moonshine developed a potion to suppress hags' "normal appetite for human flesh"), then all of the other answers must be false, including the one that says Inferi cannot speak.
- ↑ http://www.pottermore.com/en/book6/chapter26/moment1/inferius J.K. Rowlingn's thoughts: Inferi]
- ↑ Harry Potter and the Goblet of Fire