Defence Against the Dark Arts

Defence Against the Dark Arts, also known as D.A.D.A, this class teaches defensive techniques to block spells, charms, curses, hexes and jinxes cast by other wizards, counteract the Dark Arts, and to protect from dark magical beasts and creatures such as the Boggart. Defence Against the Dark Arts is taught to Hogwarts students from the first year to the fifth, with the option of N.E.W.T. classes in the sixth and seventh years for students who qualify.

Tom Marvolo Riddle twice applied for the Defence Against the Dark Arts position, the first time shortly after graduation from Hogwarts. He was refused both times. According to Dumbledore, after the second refusal, no Defence Against the Dark Arts teacher remained at Hogwarts for more than one school year. Dumbledore believed that this was due to Voldemort placing a curse on the position.

When he first came to Hogwarts as a teacher, Severus Snape applied to teach Defence Against the Dark Arts. Dumbledore refused, and instead offered Snape the position as Potions Master, which he accepted. As D.A.D.A. teachers left the school, Snape regularly reapplied for the position, and was denied each time, in what Snape assumed was Dumbledore's fear of his relapsing as a Death Eater. When J. K. Rowling was asked for the reason Dumbledore would not give Snape the job, the author responded that Dumbledore believed that teaching Defence Against the Dark Arts would bring out Snape's worst side, though Dumbledore finally relented in Harry's sixth year. 

As D.A.D.A. teachers came and went at Hogwarts, it produced inconsistent learning from year to year, as the quality and style of teaching varied widely from teacher to teacher.

By the time Harry Potter came to Hogwarts, belief in a jinx had taken hold on the outside, and new teachers became difficult to recruit for the position. Gilderoy Lockhart was said to be the only applicant to replace Quirinus Quirrell. Three years later, belief in the jinx was so widespread that Dumbledore was unable to find a new teacher, and the Ministry of Magic appointed Dolores Umbridge to the job. After Umbridge was removed for her abusive nature, Dumbledore finally gave Snape the position.

Each of the D.A.D.A. teachers in the first six books followed a similar pattern: each (with the exception of Snape) was an entirely new character, each was chosen out of necessity, due to the loss of the previous instructor and the absence of other applicants, each meets Harry before he arrives at Hogwarts in the respective year (with the exception of Mad Eye Moody who was only mentioned in passing), and each physically (or magically) attacks Harry during school term, either intentionally, or accidentally as in the case of Remus Lupin. Ironically, Harry's best subject is DADA.

List of Defence Against the Dark Arts professors

 * Galatea Merrythought
 * Employed some fifty years prior to the Harry Potter series. Lord Voldemort sought unsuccessfully to succeed Professor Merrythought in the post.


 * Quirinus Quirrell
 * Quirrell was the Muggle Studies teacher at Hogwarts. After some time in the position, he travelled throughout Europe for a full term. After his return to the school, he was appointed as D.A.D.A. teacher, receiving little respect from students for his stuttering and jittery behavior, supposedly from encountering vampires somewhere in Romania. He was killed at the end of the year after attacking Harry, sustaining excruciating pain while supporting the fragmented soul of Lord Voldemort in his own body.


 * Gilderoy Lockhart
 * Lockhart's tenure ended when he attempted to attack Harry Potter and Ron Weasley outside the Chamber of Secrets, and was hit by a backfiring Memory Charm from Ron's malfunctioning wand. Lockhart was admitted to St Mungo's Hospital for Magical Maladies and Injuries with amnesia. Lockhart was regarded by the students and teachers largely as a joke and the majority of the school was elated to see him go.


 * Remus Lupin
 * Lupin resigned after being revealed as a werewolf, out of fears that the parents of the students would not accept a werewolf as a Hogwarts teacher. Nevertheless, Lupin was enormously popular with the students and teachers, widely regarded as an effective, competent, and fair instructor and perhaps the best Defence Against the Dark Arts professor. Severus Snape stood in for Lupin as D.A.D.A. instructor on a monthly basis during the school year.


 * Alastor Moody, a.k.a. Barty Crouch Jr
 * Moody, a retired Auror with the Ministry of Magic, was brought out of retirement to replace Lupin at Hogwarts, and keep a protective eye on Harry Potter. As an Auror, Moody possessed many special magical devices, including a Sneakoscope, Secrecy Sensor, Foe-Glass and other Dark detectors. He later turned out to be an impostor – Barty Crouch Jr in disguise – having abducted the real Alastor Moody shortly before the school term began, using Polyjuice Potion to take on Moody's appearance. Crouch (as Moody) was nonetheless effective, teaching the students true defensive skills and actively demonstrating the power of the Dark Arts. After the discovery of Crouch's secret, Moody was released from captivity and returned to retirement; while Barty Crouch Jr, as an escaped prisoner from Azkaban, received the Dementor's Kiss. An interesting thing to note about Moody's period as teacher was that he briefly mentioned that he was only hired for the year anyway; whether this was truly the case or whether Crouch was lying at the time is left ambiguous.


 * Dolores Umbridge
 * Umbridge was assigned to the position acting as an agent for the Ministry of Magic, and was later named High Inquisitor as the Ministry worked to gain control of Hogwarts. As D.A.D.A. instructor, Umbridge taught only theoretical aspects of defence and topics like conflict avoidance and fleeing, in stark contrast to practical combat and resistance teachings of the previous two D.A.D.A. instructors. During Umbridge's tenure, Harry, along with Ron and Hermione Granger, provided clandestine D.A.D.A. instruction for their fellow students, based in part on some of the experiences Harry gained in his conflicts with Voldemort and others. They formed Dumbledore's Army, a secret club dedicated to training interested students in the practical elements of wizarding combat that Umbridge refused to teach. Umbridge was known to impose harsh punishments on Harry during her term, such as writing lines in his own blood during detention, as a way of forcing Harry to renounce his belief that Voldemort had returned to power. She challenged Dumbledore for his position as Headmaster, due to his support for Harry. Umbridge was removed from Hogwarts after Voldemort and his Death Eaters attacked at the Ministry of Magic, which proved that he had returned to power; and also proved the need for practical D.A.D.A. instruction for Hogwarts students.


 * Severus Snape
 * Snape assumed the post of D.A.D.A. instructor, unexpectedly by most of the students, and was replaced as Potions Master by Horace Slughorn. Little is said about Snape's tenure as D.A.D.A instructor other than that he seemed to focus on non-verbal spells and was looking after Draco Malfoy, who was acting enigmatically, for much of the term. He and Malfoy fled the school after the Battle of Hogwarts, during which Snape killed Albus Dumbledore. The next year when Voldemort took over the Ministry, Snape was appointed headmaster of the school.


 * Amycus Carrow
 * In September of 1997, Carrow became the Defence Against the Dark Arts Professor at Hogwarts though it became more of a Dark Arts class. He was arrested after Voldemort fell, and it is unclear who took over after him.