Dark Arts

The Dark Arts are not taught in any classes at Hogwarts, though Defense Against the Dark Arts may mention the spells. This magic must be self-taught or taught by another outside of school.

Fiendfyre

 * Fiendfyre is an unstoppable cursed fire whose flames take the shape of fantastic creatures that appear to stalk those caught in its path. While intermediate wizards can cast the spell, only advanced users can control it... which is an important key to using it successfully. The fire cannot be extinguished by water or fire-stopping charms, and the spell's flames may have some independent consciousness. Intermediate users must use extreme caution as they cannot stop the fire once they cast it and may very well perish in the flames themselves.

Fleo

 * Fleo fills the victim's ears with the sound of their own screaming, blocking out all other sounds and heavily disrupting any thought process. Can be willed away if the victim is strong enough, or stopped by finite incantatem.

Avada Kedavra

 * Avada Kedavra causes a bright green flash and a rushing noise; the curse causes instant death to the victim. There is no known counter-curse or blocking spell (with the exception of the curse striking another spell mid-flight, negating both), although the caster can be interrupted, the victim can dodge the green jet, hide behind solid objects (which burst into flame when hit by it), or, if the casting wizard is not sufficiently competent, the curse may be completely ineffective. It is one of the three unforgivable curses; the punishment of the use of this spell on another human being burned at the stake.

Crucio

 * Cucio inflicts intense pain on the recipient of the curse. The pain is described as hot knives being driven into you and can drive a person insane if used in excess. This curse is affected by the caster's emotions and often fails if the user doesn't have his whole heart into making their target suffer. This spell is an Unforgivable Curse, so the punishment is capital punishment.

Imperio

 * Imperio places the subject in a dream-like state, in which he or she is utterly subject to the will of the caster. However, those who are strong willed may learn to resist it. The use of this curse on another human results in capital punishment.