Bitchmeister is the bitch of bitches. Meister is the German word for master. Bitch can mean basically anything based on the context. It can be very negative and very positive.
Bitchmeister is also a person calling others bitches. See e.g. the bitchmeister blog on hans-jschmid.com, a German blog where a guy calls others bitches and "my bitches".
hans-jschmid.com is the bitchmeister.
n. (from English "bitch" for female dog, and German "Meister" for master). A woman who is the worst-tempered, schemingest, full-of-herself, back-stabbingest waste of human flesh imaginable.
If Hillary the bitchmeister becomes president, I'm shooting myself.