So... Take this with an open mind and thought process.
Here we go!
My argument is that the So called Devil is a good guy and the so called God is a Bad Guy.
Hear me out.
So you have god and the devil. And according to the three Abrahamic religion they are of the opposite spectrum and therefore they will clash in terms how to do things.
So let me give you an idea or the reason why I think that the devil is Good and the GOD is bad news for "Good People" and only good people.
OK, so you have someone who's murdered a hell of a lot of people and thus when he or she is caught and given the death sentence( a rarity among developed nations). So the time comes and he or she grasps the notion of the impending death that is to be befall them, so it strikes them so hard that they switch off their killer in them and they see realise what they have done and they pray to GOD and since it's an honest prayer, so the dude up there is all moved and he forgives him. So let me put this into perspective: he only did this because he was put into this death and eternal hell so he had no other choice, so it was not out of the goodness of his heart but out of last desperate attempt to save him from what he deserves.
So the people he butchered did not get a chance of redemption but the murderer got redemption, because he killed them from afar and they had no chance of survival, unlike him who knew of the death day, they had no previous warning.
Since GOD forgave him because of that honest prayer, he's now sipping amber nectar with the Man himself while his victims went without justice.
Here's the Devil.
So let's go from the beginning.
So the angel who will fall has been watching the MAN give chances to bad people and save them from torment just because of a prayer was not happy.
So he does what you all read in the holy books and so he ends up in the abyss of the realm bellow and becomes the Dude.
So he is good in my opinion as he punishes the bad people that do bad things to just about anyone, and frankly that type of beings are heroes in my book any day.
Let's not forget his (alleged) dealings with some notable humans whom have given birth to some fantastic works of art that will go on to feed the soul of the seeker and just about anyone that gazes and listens and read's them. Like they say any form of art is a blessing.
So The devil has made our lives much more interesting and all the while the Man upstairs keep's on smiting us when someone who he has created causes some sort of shit and messes it up for the rest of us. And whom he'll save because of a damn prayer.
So...I'm not here to tell you whom to root for but if you live the way you want, you may do that, but please make sure you contribute to the society, unless a chosen life as a vagabond or something along those lines, but do not hurt another life, if you can avoid it WHY NOT.
The way I see it, the dude upstairs created all life as he saw fit and we are also like an animal and therefore when you stand in front of him or something or someone, being judged and you will get the same pedestal as a chicken or a fat happy king so be nice when possible(but not all the time, so they don't walk all over you).
Just to be sure pray to both, and cover all your bases.