This is how I see it. I believe in one God, thats it.
God (or the Universe) is everything. He is the quantum field from which everything that exist is born from and dies to. The black on the left of the above picture represents the quantum field aka the non existence. The right side of the picture is things that do exist. And everything that exist has an opposite. Good has bad as its opposite. So if the devil does exist, he is on the existing side of the picture, the right. which means he was created from the same non existence that me and you were. So he can combat his opposition, which is good, all he wants. But he can't combat or overthrow the non existence side. In order for him to even get there he has to cease to exist. So it makes since that for anyone to say that the devil even has a chance to overthrow God one day is blasphemy. And think about it like this. Adapting this mentality means that no evil can effect you. The bad that you'll experience is the bad you bring into your life, which means you have control, and you wouldn't hurt you. Plus, take a good look at the picture. IT MAKES SENSE! All of our lives we've been told, believe that God is this, and believe that God is that. Now you have something a little more solid to hold onto.
And if he does exist, obviously we are cut from the same cloth, are we not. We're both born from the realm of non existence (or the quantum field) into existence. That just makes him a worthy opponent. I manifest my future. I control the next steps. And if I choose not to let him be a part of that, then thats what I'm going to do. And I suggest you do the same. To give the Devil life, and to give him a hold over a part of your life is just plain stupid, counter productive, and pointless. Just saying or thinking that he has some control over you, gives this false deity control. Don't give him that power. God gives us life. God gives us attention to spend on whatever we want to give our attention to, and you're going to spend it on the Devil?! I can think of a million better things to spend it on. You manifest your own future. And if you choose to manifest some deity messing up your life then go ahead. You'll get tired of it then return to this page with an open mind and learn something. Then your life, without that anchor, will forever be changed. And when you notice the world and circumstances around you begin to shift according to what you've been thinking about, you'll know the power you possess.
Now I'm not saying that I know for a fact that there is no Devil. That would be asinine and put me in the same category with the rest of the population that swears that they know for a "fact" that there is one (smh). What I'm saying is that when you use a bit of common since and have an open mind that you don't know everything about everything, the conclusion is that his influence, and more than likely he, does not exist. Every bible reference to the Devil or demons, in my opinion, is referring to inner demons and how we can torture ourselves internally (mentally) which undoubtably manifest more poor situations and more mental torment over and over again.