I'm going to repeat myself:
People that identify themselves with Satanism don't always believe there is a "Satan" at all. Satan may be a symbol to them, a deviant from the norm, a rebellious figure, something that reflects their own search for individuality by rejecting what they are told is or isn't true or what they should or shouldn't do. In these cases, they are more so just aggressive Atheists than anything else.
Some Satanists follow tenants of self-perservation that basically states to worry for themselves first and anyone else second, an eye for an eye, etc. They may see themselves as a "god" (Sometimes in a narcissistic way other times not so much) on earth and any worship they give should go to themselves primarily. Again, even if they believe this, they still may not necessarily believe there is a Satan.
And then there are a number of folks and cults that believe in an evil overlord and worship him in hopes of being his minions. There are far less of them than you would think, though.
I hope that clears things up. :o
**For the record, though, there are thousands of more cases and generally, like any Faith, religion, or viewpoint it changes from person to person.**
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