Evil is a higher power than you for you never know exactly what harm it is doing or why. Uncertainty prolongs it and empowers it.
It is only natural that it will be actually personified or as good as. Fear always involves a level of projection - we create our fears to a certain extent. As we fear evil, projection is going to be put into the framework we think evil is in and into the evil itself.
We act, and often talk, as if it is an intelligence – effectively an intelligence if not actually one - or as if it really does have a mind of its own. If it does not, we give it a mind. We project its mental powers into those who we think wield and align with it – they “become” some kind of incarnations. We do that to ourselves too when we do evil. Our reactions to evil show that we treat it and think of it as more than a mere failure.