I think that is a discussion for a different post, as this one does not argue that Satan does not exist (I confess my own leanings but do not argue the position thoroughly) nor do I challenge the existence of a literal hell.

What I am arguing in this post is that the figure of Satan, as it functions and it has been thought of in traditional Christianity, confounds Christian claims to monotheism and is itself fundamentally heretical because of this. 

Let's keep the conversation, as best we can, to this. I am not trying to dismiss your comments, but it's difficult to spend an entire post arguing one way only to have it switched. If we were discussing your questions, I would have written a different post! :) We can exegete passages on "the satan" (literally "the adversary") later and what Jesus meant by those passages. (Was he using the satan as a metaphor for Peter being an adversary — the literal definition of the Satan — in obstructing his decision to die on the cross? And questions of the like are enough for exploration on their own)

I welcome your thoughts on whether the figure of Satan comports with monotheism and how to reconcile monotheism with the notion that two supernatural beings are locked in eternal battle — neither having definitively defeated the other as both, as traditional Christianity understands it, are still warring.