The greatest advantage we have is that humans cannot see heaven and all of its grandeur. Moreover the reality in which humans live makes the perception of heaven seem illogical and even ridiculous. The long life span of humans allows for them to grow attached to reality on Earth, and gives tempters an enormous advantage.
The greatest advantage of the enemy is the faith of its followers. Unfortunately, faith is contagious and has a virus like tendency of spreading. The enemy also has the advantage of once being human, and therefore knowing much more about how humans live and how humans respond to different situations.
While the conflict between the enemy's leader and our father below is complex, it is essentially the battle is between apparent reality and faith in another better place. Once you understand the enemy completely, you can better understand yourself and your purpose. When you become unsure as to what you should do, think of what the enemy would do and do the opposite.