Just a few questions.
Why did God create Satan?
Why does he allow him to influence us?
Why did God send Satan to eternal torture; why not eternal boredom?
Why fire?
I don't know why God created angels or man, but satan was created and he was perfect in his ways, until he sinned.
I would more look at the influence which comes from sin in our lives, our hearts etc, then to satan as for influecing us personally. however maybe i shoudn't state such as i'm going by my personal experience.
seems to be satan more effects the world, by encouraging those to disbelieve in God, and to decieve others from the truths of God, one big deception to non believers is that there is a hell. He also tries to discourage those from coming to God(Jesus) very much so.
Why does God allow it; because He also made angels with free will it appears, as 1/3 of the angels rebelled against God along with satan, and God does not hinder free will, however if you go by the book of Job, we see in that instance, in the 1st two chapters at least, that satan needed pemission to do what satan did to Job.
So, many Christians assume from this then it is God who allows evil to be done, since they believe satan must seek permission each time, however the bible doesn't state such, only reveals the bit on job..may be in the bible more about such, but i'm not aware of it (which doens't mean a lot.)
Don't know why to eternal torture and fire, men will suffer the same, no differnent. I imagine it will be boring.