I don't know where you are coming from in asking about this. How knowledgeable are you about these things?
I spent 2 years in Africa as a Peace Corps teacher. In Africa the shaman is called a "zoman". It is the same word with a slightly different pronunciation. In fact the word shaman is used around the world in very different cultures for the same thing.
A zoman is a witch doctor. They are greatly feared by the tribesman. They have more power than the village chief. Some of them could sometimes perform healings through occult arts. They rule the people with fear and occult rituals. They rule with a secret society mechanism. The boys are taken from their mothers just before puberty and taken to bush school. There they are circumcised and taught the secrets of the village clan. Some of them never return. Many of them still practiced child sacrifice.
When I was trying to sleep, I could hear the drums pounding in the village in the distance. Quite frightening. They would go all night. I was warned never to approach the village during those times. I took that seriously.