the devil seems more "real" to many because his deception is the illusive material world.
Many people do not see God because they are attached to this illusion and cannot see spiritual truth.
Without spiritual knowledge it may seem to many that evil reigns. But that is because our souls ar conditioned in this material energy. As long is this persists will be as long as we are susceptible to the duality of good and evil. God, being the author of this duality, transcends it. God, Himself, is not evil. Nor is He good, (as far as the duality goes). But, one should come to understand God's transcendentality as being supremely Good, which is beyond our relative material conception of "good versus evil".
One could say that the devil is the perpetual duality of pleasure and pain. There is no pleasure without pain and vice versa. Same with good and evil.
But, God is eternal bliss. Pleasure and pain, good and evil, exist under Him, but He is not susceptible to them.
Another way to put it is with the example of knowledge and ignorance...
We (individual souls) will always have both knowledge and ignorance. You cannot have one without the other. We will never have complete knowledge because we will never be God. God, on the other hand, portrays in His being no ignorance, whatsoever.
The point is, many people only see the duality of the material world and perceive that if they want to feel good they will have to remain susceptible to feeling bad. Hence, many may feel the devil, (material illusion of duality), is more real than God...