Witch

Basically, humans born with special powers.

Spells

Witches can cast spells to affect the world around them. When they do so, they have to direct the magic through something. A bit of excess magic is expelled into whatever object they use. Almost all witches use a wand of some kind, typically the same over and over, as the object stores the excess magic. If they try to use their hand/finger to do so, the excess magic will either go back into them and harm them as it was done improperly or explode the appendage used for the spell. Most witches will only ever use their hands instead of a wand in an absolute life or death emergency.