What is a Shaman?

I've been researching shaman, but can not find anything about shaman.
what little I found is that they are beings who invoke spirits, demons and are able to easily defeat a vampire.
I would like to know more about shaman, someone knows?

Hi Diogo, just out of curiosity, what other types of information are you seeking, and where did you hear/read that a Shaman can easily defeat a vampire?

I read on a website, now I do not remember.

This doesn't talk about any kind of fighting between shamans and vampires, but it inspires an interesting train of thought about shamans sometimes "being" vampires:

http://www.whitedragon.org.uk/articles/vampire.htm

First of all thanks for the link, it is written very interesting things, but in fact there seems to be a connection between vampires and shaman, and like you said. "but it Inspires an interesting train of thought about shamans sometimes" being "", is true, I had no idea.
Really is very interesting and amazing.