Satan is evil. He is the bad guy, trust me on this. He does what he does because he hates all life forms. Mainly humans. God sent him to be the ruler of "Hell" as a punishment. Tricking him into thinking he was getting what he wanted, to torture and kill humans, in reality he was just saving God from doing something he knew needed to be done but couldn't come to do himself, and that is punishing the wicked. While the wicked must be punished God still loves all life forms, plus Satan is the best at sadistic torture to teach the wicked the error of their ways. Many may say God is a coward for not doing this himself and tricking his brother into doing it for him. But think of it this way. Could you torture your own son, daughter, or loved one? The answer to that question for any good human is, undoubtedly, No. Long story short Satan is evil and weak, don't be fooled by him. That is all.