Defence Against the Dark Arts

• Type: Hogwarts Core Subject; Branch of Practical Magic
• Owners: This position was held by a new professor each year from 1991-1998 due to a jinx.
• Classroom: The Defence Against the Dark Arts Classroom, located on the first floor of Hogwarts Castle.

Defence Against the Dark Arts (often abbreviated as D.A.D.A.) is a core subject taught at Hogwarts School of Witchcraft and Wizardry. The curriculum focuses on providing witches and wizards with the practical and theoretical knowledge to defend themselves against the Dark Arts. This includes learning how to counter hostile spells, defend against Dark Creatures, and navigate encounters with Dark Wizards. The subject matter is highly practical, involving learning and casting defensive spells such as the Disarming Charm (Expelliarmus), the Shield Charm (Protego), and the Stunning Spell (Stupefy). Students also study a variety of malevolent beings, including Boggarts, Red Caps, Grindylows, Werewolves, and Dementors. The curriculum is designed to prepare students for their O.W.L.s in their fifth year and N.E.W.T.s in their seventh, assuming they continue with the subject. The effectiveness and focus of the class varied dramatically depending on the professor.

The Defence Against the Dark Arts teaching post at Hogwarts was famously jinxed by Lord Voldemort after he was denied the position by Headmaster Albus Dumbledore decades prior to Harry Potter's attendance. According to Dumbledore, no professor held the position for more than one year after the jinx was put in place. This jinx remained in effect until Voldemort's final defeat. The known professors during the 1990s and their fates are as follows:

1. Quirinus Quirrell (1991–1992): Secretly shared his body with the spectral form of Lord Voldemort. He died in the Underground Chambers after attempting to steal the Philosopher's Stone when Voldemort's spirit abandoned his body.
2. Gilderoy Lockhart (1992–1993): A charismatic but incompetent fraud who took credit for other wizards' accomplishments. His tenure ended when a backfiring Memory Charm he cast with Ron Weasley's broken wand permanently erased his own memory. He was subsequently institutionalized at St Mungo's Hospital for Magical Maladies and Injuries.
3. Remus Lupin (1993–1994): The most competent and popular professor of Harry's time. He taught students practical defence against a wide range of Dark Creatures. He resigned after Severus Snape revealed to the school community that Lupin was a werewolf.
4. Barty Crouch Jr. (as Alastor Moody) (1994–1995): A Death Eater who used Polyjuice Potion to impersonate the famous Auror Alastor Moody. He provided Harry with highly advanced, practical training with the ulterior motive of guiding him to Voldemort. He was exposed at the end of the school year and subjected to the Dementor's Kiss before he could testify.
5. Dolores Umbridge (1995–1996): A Ministry of Magic official who refused to teach any practical magic, forcing students to read from a deeply inadequate, theory-only textbook. Her oppressive methods led directly to the formation of Dumbledore's Army. She was removed from her post at the end of the school year.
6. Severus Snape (1996–1997): After years of seeking the position, Snape finally became the Defence Against the Dark Arts teacher. His lessons focused on non-verbal spells and a deeper understanding of the Dark Arts themselves. He fled Hogwarts after killing Albus Dumbledore.
7. Amycus Carrow (1997–1998): A Death Eater appointed during Voldemort's control of Hogwarts. The subject was renamed simply “Dark Arts,” and students were forced to practice curses, such as the Cruciatus Curse, on students assigned to detention. He was defeated and captured during the Battle of Hogwarts.

The Defence Against the Dark Arts class serves as a crucial barometer for the state of the wizarding world and is central to Harry Potter's development as a wizard. The yearly rotation of teachers is a significant plot device, introducing new characters, conflicts, and forms of magic each year. The quality of instruction directly impacts the students' ability to survive. Remus Lupin's teaching, particularly the Patronus Charm, was vital for Harry's survival against Dementors. Conversely, Dolores Umbridge's refusal to teach practical defence created a vacuum that Harry, Ron Weasley, and Hermione Granger filled by creating Dumbledore's Army, a secret student-led defence group. This organization became instrumental in training students for the Second Wizarding War and played a key role in the resistance at Hogwarts in the final book. The skills Harry learned and taught were fundamental to his and his allies' fight against Lord Voldemort and his Death Eaters.

• J.K. Rowling has confirmed that the jinx on the Defence Against the Dark Arts post was broken with Voldemort's death, and that a permanent teacher was in place by the time Harry's children attended Hogwarts (J.K. Rowling interview).
• Prior to Tom Riddle's application, the post was held for fifty years by a professor named Galatea Merrythought (Pottermore).
• In the film adaptation of Harry Potter and the Half-Blood Prince, the Defence Against the Dark Arts Classroom is relocated to a much higher floor in the Defence Against the Dark Arts Tower, contrary to its book location on the first floor (film).