I am Alpha and Omega, the first and the last.
The commonplace and simple religious understanding of God is of a single nature - to think that God is purely based off the basic principle of goodness. Yet, this doesn't manage to sit well with me. How could any being - holy or otherwise - be so perfectly aligned to one side of morality, while we mortals are forever doomed to trudge along the dividing line, slipping back and forth between the darkness and the light? For after all, were we not made in His* image? It is clear from just living that the world around us is a reflection of our own mislaid souls - both are capable of unquestionably fantastic things, while at the same time proficient at destruction.
Indeed with this singular comprehension of God, one could argue that Satan provides the opposing counter-weight. One pure good, the other pure evil - two essences - that lend themselves to the label of sharing a dual existence. But then, it also understood that Satan is and always will be weaker than God, the good one - the better one.
It is here that we also run into another problem. Duality calls for balance between the forces - one can't have more of a pull than the other - So here is another theory: What if instead of God and Lucifer being two separate - but in no way independent - beings, they were two sides of the same individual? Such an individual would be a much more accurate demonstration of our own psyches - it would be easier to perceive our creation from its hands than the hands of a do-gooder, no? For why and how could something of pure light make such muddied creatures. How could it had even known or possess the ability to grasp shadows, unless it did in fact leave some in its wake?
To me, it is this version of god that makes the most sense - that seems the most human.
Or course, perhaps God is truly neutral in our lives, merely being without much sway towards anything?
*Who is to say God is male of female? Doesn't that bring up the question of duality itself, should we give the concept of god a gender? Where is the counter-part?