It is wrong belief that negative effect of energy creator are doing special sadhana but anybody may creates negative effects of energy with their strong determination.
Generally in India AGHORI, NAGA SADHU, or KAPALIC are applying black magic on peoples but it is is 100% wrong, infact they are trying to connect with their specific method of sadhana which is fearful.
Black magic is not a specific sadhana but any sadhana offered with negative intention is called black magic.
wrong beliefs in people mind
General people know black magic comes in action only in cremation space but it is wrong , it occurs any where.
How black magic works
If you are weak by mind than only black magic can effect you.
how to avoid it
Believe in yourself and your strength which is naturally with you since your birth.