I think there are two kinds of evil powers.
1. Sourced from LUcifer (the Devil) and his cohorts flung down to the earth after His/Their rebellion against the Almighty and...
2. From heavenly Angels that came down from heaven and had relationship with the Daughters of Men.

This is why we sometimes see or must have heard of Demons in conflict with eachother (like you've heard of white and Black magic). Some demons being "friendly" with man [in the case of white magic] and the other "hostile" [black magic]. Some of these evil powers are witnessed in some persons without the host knowledgeable of its source. discuss.