<P> According to Snape, the Dark Arts "are many, varied, ever - changing and eternal...unfixed, mutating, indestructible". In magical dueling, there are any number of spells that may be used to attack, immobilise, or disarm an opponent without causing pain or lasting harm; however, spells such as the Cruciatus Curse or Sectumsempra, judged to be Dark by reliable authorities, wound or seriously distress a victim in some way . Dark spells can be classified into three groups: jinxes, hexes & curses . </P> <P> In the wizarding world, use of the Dark Arts is strongly stigmatised and even illegal; however, these spells are prevalent enough that even before the rise of Voldemort, many schools, (including Hogwarts), taught Defence Against the Dark Arts as a standard subject . Techniques include anti-curses and simple spells to disable or disarm attackers or fight off certain creatures . Some schools, such as Durmstrang, teach Dark Magic . A Dark Arts class is also taught at Hogwarts while it is under Death Eater control . </P> <P> The Unforgivable Curses are some of the most powerful known Dark Arts spells . They were first classified as unforgivable in 1717 . Used by the books' villains, such as Voldemort and the Death Eaters and in some cases the Ministry of Magic, their use inspires horror and great fear amongst others . The curses are so named because their use is forbidden and unforgivable in the wizarding world and is punishable by a life sentence in Azkaban . The only exception is if a person is proved to have done them under the influence of mind control . These curses are thus very rarely used openly . </P> <P> The Unforgivable Curses include: </P>

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