Question: Which organisation did this faculty of the wizarding school Hogwarts, with whom Harry prepares the final battle against Voldemort in his sixth year, found?

Context paragraphs:
Harry Potter and the Half-Blood Prince: Harry Potter and the Half-Blood Prince is the sixth and penultimate novel in the "Harry Potter" series, written by British author J. K. Rowling.  Set during protagonist Harry Potter's sixth year at Hogwarts, the novel explores the past of Harry's nemesis, Lord Voldemort, and Harry's preparations for the final battle against Voldemort alongside his headmaster and mentor Albus Dumbledore.

Harry Potter and the Forbidden Journey: Harry Potter and the Forbidden Journey is a motion-based dark ride located in The Wizarding World of Harry Potter themed areas of Islands of Adventure in Orlando, Florida, Universal Studios Hollywood in Universal City, California, and Universal Studios Japan in Osaka, Japan.  The ride takes guests through scenes and environments in and around Hogwarts Castle from the Harry Potter series of books and films.  Mark Woodbury, president of Universal Creative, described the ride as an in-depth look at the world of Harry Potter, which utilizes never-before-seen technology which transforms "the theme park experience as you know it".  The ride first opened at Islands of Adventure with "The Wizarding World of Harry Potter" on June 18, 2010, at Universal Studios Japan on July 15, 2014, and at Universal Studios Hollywood on April 7, 2016.

Death Eater: Death Eaters are fictional characters in the "Harry Potter" series of novels and films.  They are a group of wizards and witches, led by the dark wizard Lord Voldemort, who seek to purify the Wizarding community by eliminating the Muggle-borns (wizards or witches born to non-magical parents).  They also try to create a new order through the Ministry of Magic and spread fear throughout the Wizarding community by terrorising and killing important officials and other enemies of the Death Eaters, chiefly the members of the Order of the Phoenix.  Although the reason why they are called "Death Eaters" has not been explained by J.K. Rowling, there is some evidence to suggest that it is a reference to their ultimate goal of preventing death and achieving immortality.

Harry Potter and the Prisoner of Azkaban: Harry Potter and the Prisoner of Azkaban is the third novel in the "Harry Potter" series, written by J. K. Rowling.  The book follows Harry Potter, a young wizard, in his third year at Hogwarts School of Witchcraft and Wizardry.  Along with friends Ronald Weasley and Hermione Granger, Harry investigates Sirius Black, an escaped prisoner from Azkaban who they believe is one of Lord Voldemort's old allies.

Harry Potter and the Philosopher's Stone: Harry Potter and the Philosopher's Stone is the first novel in the "Harry Potter" series and J. K. Rowling's debut novel, first published in 1997 by Bloomsbury.  It was published in the United States as Harry Potter and the Sorcerer's Stone by Scholastic Corporation in 1998.  The plot follows Harry Potter, a young wizard who discovers his magical heritage as he makes close friends and a few enemies in his first year at the Hogwarts School of Witchcraft and Wizardry.  With the help of his friends, Harry faces an attempted comeback by the dark wizard Lord Voldemort, who killed Harry's parents, but failed to kill Harry when he was just 15 months old.

Harry Potter and the Order of the Phoenix: Harry Potter and the Order of the Phoenix is the fifth and antepenultimate novel in the "Harry Potter" series, written by J. K. Rowling.  It follows Harry Potter's struggles through his fifth year at Hogwarts School of Witchcraft and Wizardry, including the surreptitious return of the antagonist Lord Voldemort, O.W.L. exams, and an obstructive Ministry of Magic.  The novel was published on 21 June 2003 by Bloomsbury in the United Kingdom, Scholastic in the United States, and Raincoast in Canada.  Five million copies were sold in the first 24 hours of publication.  It is the longest book of the series.

Magical creatures in Harry Potter: Magical creatures are a colourful aspect of the fictional wizarding world contained in the "Harry Potter" series by J. K. Rowling.  Throughout the seven books of the series, Harry and his friends come across many of these creatures on their adventures, as well as in the Care of Magical Creatures class at Hogwarts.  Rowling has also written "Fantastic Beasts and Where to Find Them", a guide to the magical beasts found in the series.  Many of these are derived from folklore, primarily Greek mythology, but also British and Scandinavian folklore.  Many of the legends surrounding mythical creatures are also incorporated in the books.  "Children ... know that I didn't invent unicorns, but I've had to explain frequently that I didn't actually invent hippogriffs," Rowling told Stephen Fry in an interview for BBC Radio 4.  "When I do use a creature that I know is a mythological entity, I like to find out as much as I can about it.  I might not use it, but to make it as consistent as I feel is good for my plot."

Albus Dumbledore: Professor Albus Percival Wulfric Brian Dumbledore is a fictional character in J. K. Rowling's "Harry Potter" series.  For most of the series, he is the headmaster of the wizarding school Hogwarts.  As part of his backstory, it is revealed that he is the founder and leader of the Order of the Phoenix, an organisation dedicated to fighting Lord Voldemort.

Harry Potter and the Half-Blood Prince (film): Harry Potter and the Half-Blood Prince is a 2009 British-American fantasy film directed by David Yates and distributed by Warner Bros.  Pictures.  It is based on the novel of the same name by J. K. Rowling.  The film, which is the sixth instalment in the "Harry Potter" film series, was written by Steve Kloves and produced by David Heyman and David Barron.  The story follows Harry Potter's sixth year at Hogwarts as he receives a mysterious textbook, falls in love, and attempts to retrieve a memory that holds the key to Lord Voldemort's downfall.

Severus Snape: Severus Snape is a fictional character in J. K. Rowling's "Harry Potter" series.  An exceptionally skilful wizard, his coldly sarcastic and controlled exterior conceals deep emotions and anguish.  A Professor at Hogwarts School of Witchcraft and Wizardry, Snape is hostile to the series' protagonist, Harry, the moment he sets foot in Snape's classroom; this hostility is rooted in Harry's resemblance to Harry's father James, who bullied and harassed Snape during their time at Hogwarts.  Though philosophically attracted to the Dark Arts and Lord Voldemort's ideology of wizard supremacy, Snape's love for Muggle-born Lily Evans, Harry's mother, eventually compels him to defect from the Death Eaters.  Snape becomes a double-agent on behalf of Albus Dumbledore and the Order of the Phoenix, and protects Harry throughout the series.

Supporting paragraphs: Harry Potter and the Half-Blood Prince Albus Dumbledore
Answer: Order of the Phoenix