In this chapter, I will talk about dark spells and curses. 

Avada Kedavra

Appearance

Avada Kedavra is a curse that can be a range of a few different colors, including blue, green, and somewhere in the middle. Sometimes, it depends on the wand casting the curse as to what color it is. For example, Wormtail and Voldemort produce a green curse, although Snape's is slightly bluer. The killing curse is a form of spell that shoots out of the wand very quickly and gives the opponent not much time to block it. The cast can go off in many directions, shooting up and around the main jet, making it look like a flash of green or blue light.

Learning

Mastering Avada Kedavra is a very hard job. The killing curse is one of the hardest of all spells to learn and can only be perfected by very powerful witches and wizards. There is no particular way to say the curse, although you must cast it in a particular way. First, you must hold your wand slightly-not far- into the air. Then you must slowly lower your wand and say the incantation clearly. If you move the wand too fast when casting the Avada Kedavra curse, there could be some major side-effects.

Crucio

The Cruciatus Curse (also known as the Curse of Torture ) ( Crucio ) is one of the Unforgivable Curses . It is one of the most powerful and sinister spells in the wizarding world . The Cruciatus curse is the curse of torture (it is one of the curses that causes the most pain, both physical and psychological).

It is not enough to just pronounce the words, you must want to cause pain and take pleasure in your opponent's suffering.

Considering the fact that this curse does not physically harm or leave any injury to the victim, it is possible that it merely stimulates the pain receptors aggressively. 

To perform this curse you must say the incantation clearly and with conviction, while moving your wand like using an whip. 

Imperio

The Imperius Curse ( Imperio ) is a tool of the Dark Arts and one of the three Unforgivable Curses . It is one of the most powerful and sinister spells known to the wizarding world . When successfully cast, it places the victim under the control of the caster, although a person with exceptional willpower would be able to resist it.

To perform this spell you must point your wand to the target and say the incantation clearly. 

Protego Diabolica

Protego Diabolica was the incantation of a powerful dark charm that allowed the user to create a protective ring of black fire around them that completely incinerated enemies of the caster who came into contact with it while leaving their allies unharmed, It could also be used as a weapon, working like Fiendfyre.