Basic Defense Against the Dark Arts

Dark creatures differ from other animals in several important ways.

• They are magical in nature
• They often do not have a complete life cycle the way a typical animal would but exist simply as a physical extension of an evil intention
• They seek actively to harm, often for no other reason than that's what they do (i.e., not for reasons of sustaining their own lives)

Dark creatures are not animals. They are actually another form of magical being. Fantastic Beasts refers to many of them as "demons," not in a religious sense, but because it describes a key aspect of them all: they exist to actively do harm and damage. This harm is different from the harm that, say, a manticore would do, since the manticore would be attacking someone to eat them. In other words, it is a predator and that's what predators do to survive.

Dark creatures, on the other hand, aren't animals. They don't have life cycles in the same sense that normal animals have. They attack for the sake of hurting someone, not simply to eat. The Red Caps are a great example. They bludgeon unususpecting travellers so that they can use their blood to stain their cloth caps red. It doesn't give them food, it doesn't allow them to reproduce, they do it purely out of nastiness. One way of thinking about it is to say that they are a physical embodiment of an evil, harmful intent. And if you think about the essence of magic being intent, Dark creatures are a physical embodiment of Dark Magic.

The department for the Regulation and Control of Magical Creatures gives a classification to all known beasts, beings and spirits. These offer an at-a-glance guide to the perceived dangerousness of a creature. The five categories are as follows:

"The Dark Arts are many, varied, ever-changing and eternal. Fighting them is like fighting a many-headed monster, which, each time a neck is severed, sprouts a head even fiercer and cleverer than before. You are fighting that which is unfixed, mutating, indestructible.

"Your defences must therefore be as flexible and inventive as the Arts you seek to undo." 

-Prof. Severus Snape

"A class that would teach students how to protect themselves in the event they are faced with something or someone that intends to cause them bodily harm. All spells can become dark depending on the intent of the caster" ~Lacy Travers

The intent of learning Defensive spells is to prepare you for anything that may come your way in life. As much as we all wish we lived in a safe world, dark wizards are still around, meeting together to create groups of people intent on taking over the wizarding world.

In order to teach proper defensive techniques it has been agreed upon that you must also learn a few of the spells that you may come in contact with that the defensive spells would prove useful against.