The identification of some items as "myth" represent my current analysis and is not intended to hinder useful discussion on the merits of such viewpoints.
The past myths about Satan include that he was ruler of demons and that he was a fallen angel. There also is no basis to say that he has possessed anyone except Judas, if possession even occurred there.
Some modern myths is that Satan does not have powers or worse that Satan is not a specific creature having continuity of person and being from the time of Genesis through Revelation. Though I think some benefit is gained in seeing that Satan doesn't confer powers upon people, at least not among any significant numbers of people.Luk 22:3 Then Satan entered into Judas called Iscariot, who was of the number of the twelve.(ESV -- e-sword.net)
When looking at John 8:44
It is seen there are two different types of entities here. One is Satan, who, by influence, is the father of a bunch of people. The other type of entity is that of people who were influenced by the devil in fulfillment of Gen 3:15.Joh 8:44 You are of your father the devil, and your will is to do your father's desires. He was a murderer from the beginning, and has nothing to do with the truth, because there is no truth in him. When he lies, he speaks out of his own character, for he is a liar and the father of lies.(ESV -- e-sword.net)
= = = =
It seems that God created Satan as an adversary to expose the wicked of the world and that Satan is a specific creature, maybe physical maybe not having to exist in the physical, that has existed from the time of Genesis until Revelation. He then can personally (not through transfer to other creatures) exercise some powers either physical or in some minds ( see Luke 4 temptation of Christ).
He may promote a spirit of disobedience, maybe design the style of behavior, but does not possess people in general.
So there are some good changes going on, but the kinks aren't ironed out.