Firstly, wtf is dicordianism?
where you trying to write discordianism? Cause i can almost see a connection there with some versions of satanism. what with the whole chaos thing....
Secondly, Satanism is such a ******** religion. There are so many different forms - all claiming to have some sort of ancient knowledge, although strangely enough usually written in crayon by crack heads. Some of them over the years have come up with some pretty intelligent ideas - but most are pretty dumb, such as drinking blood to gain "power" or sex orgies and unholy communion (which consisted of eathing a wafer biscuit covered in the poo of some lady prietess...mmm tasty)... - I mean, as much as i might question the logic behind the major religions of today, at least they don't ask for burnt offerings... anymore that is.
I'm guessing the human nature point revolves around the "do unto others as the do to you" because we are all just animals notion which many of the more intelligent satanists claim they believe.
Finally, Atheism does not involve any set belief on human nature. An Atheist could adhere to Satre, Plato, MArx, freud, Kant, Lorenz, Skinner or many other philosphers' ideas on hunature. The only common link is the disbelief in a deity. Just because we don't believe in a god does not mean we have the same idea of the nature of man. Personally, I like the Marxist idea that man is capable of both good and evil depending upon their socio-economic factors, but above that i think people are genetically predisposed to be nice as it is an advantageous in the evolutionary sense and that it is only through oppression, percieved injustices, and a lack of rational discourse that people become capable of the unbelievable cruel acts that are committed by man from time to time.