I don't know if there are any theists here. I would hope not. Some atheists are hung up on Satan. To me that just says that they're still hung up on Christianity, so much that they have to be ornery and do everything the opposite of it. I never cared enough about Christianity to care about Satan.
I doubt you will get many theist responses on this site. The Devil is likely another aspect borrowed from Zoroastrianism - the good/evil symmetry. But hey, somebody has to do the job, gods busy killing some middle eastern tribe.
That's the premise of G. B. Shaw's Don Juan in Hell it's a great satire by one of the premier Atheist.
God's not only a humorless dick he's also a sadistic psychopath.
OTOH, The Devil (Ole Scratch) seems to be portrayed, in modern literature, as a charismatic con man that will cheat you out of your teeth - but always honors his bargains. And the stupid are his prey.
Hell looks better all the time.