I just happened to start loking int othis, as their are many different thoughts on Satan, even amonst Christians.
When I was taking the discussions for the LDS church, I was told that Satan used to be an angel who wanted to be 'higher than the most high' Bigger than God....he fell, blah, blah, blah...but also, just like Jesus, he is, was, or literal brother.
Now, I have been doing some more reading and found this out:
Satan, who name was Lucifer(this name was used only once in the Holy bible) used to be one of the most revered(sp?) among God's angels, he was Jesus' right hand man. His name(Lucifer) means Morning Star, or Bright One, so it seems that Lucifer used to be a great angel.
But then I read that Satan has always been bad. He is the father of lies and hate. Of course now that you ask I don't have the websites, but did a search and found this one:http://www.bible.ca/su-devil.htm
** I haven't thoroughly read through this site, so if you find anyn flaws, they aren't mine