If you read Genesis 3, even superficially, you will see that Eve is conversing with a serpent and not with a figment of her imagination. If she is really talking to a fallen angel, I challenge you to demonstrate where he shows up.
Notice that in Genesis 3:1 the serpent is described as a special creation "more subtil" or intelligent than any other non-human creature and had the ability to reason and speak. If the serpent was merely the "ventriloquist's dummy" for a fallen angel why would that be necessary? Why, in the punishment meted out in 3:14, is the serpent punished if it were merely the tool of an evil angel? Why does Paul say:
2 Corinthians 11:3 But I fear, lest by any means, as the serpent beguiled Eve through his subtilty, so your minds should be corrupted from the simplicity that is in Christ.
Who beguiled eve "through his subtilty"? Paul says it was the serpent. Whom do you say it was?
In the history of Eve, Adam, and the serpent in the garden, we have a wonderful illustration of the process of temptation leading to sin and its consequence, death, and God's love and mercy in redeeming his children from that awful consequence.
We see Adam and Eve made in the image of God. We have the Word of God in a simple commandment, the "mind of the spirit". We see, in the serpent, a vivid representation of the "mind of the flesh" which is the source of temptation. This is the conflict in the world: the mind of the flesh vs the mind of the spirit. Read Romans 6, 7, and 8 for an excellent treatment of this subject.
Also, John says:
1 John 2:15-17 Love not the world, neither the things that are in the world. If any man love the world, the love of the Father is not in him. For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world. And the world passeth away, and the lust thereof: but he that doeth the will of God abideth for ever.
Note how John's characterization of "all that is in the world" exactly matches the process of temptation in the garden:
Genesis 3:6And when the woman saw that the tree was good for food [lust of the flesh], and that it was pleasant to the eyes [lust of the eyes], and a tree to be desired to make one wise [pride of life], she took of the fruit thereof, and did eat, and gave also unto her husband with her; and he did eat.
Also note that John says that this is all that is in the world. If this is "all" where is the fallen angel?
James also describes the process of temptation which exactly corresponds to the process we have seen in Genesis and in John:
James 1:13-15 Let no man say when he is tempted, I am tempted of God: for God cannot be tempted with evil, neither tempteth he any man: But every man is tempted, when he is drawn away of his own lust, and enticed. Then when lust hath conceived, it bringeth forth sin: and sin, when it is finished, bringeth forth death.
Note that James sees only two alternative sources to temptation - God or our own perverse nature. James declares that it is impossible for temptation to sin to come from God, therefore we alone bear the responsibility. Where is the fallen angel? Nowhere in the Bible where the process of temptation and sin is described is there a mention of some figment of pagan imagination - a demon, imp, or fallen angel. Here's what the Lord himself says about the origin of sin:
Mark 7:21-23 For from within, out of the heart of men, proceed evil thoughts, adulteries, fornications, murders, thefts, covetousness, wickedness, deceit, lewdness, an evil eye, blasphemy, pride, foolishness. All these evil things come from within and defile a man."
If you would like to continue this conversation I would be happy to do so. However, if you plan to use Isaiah 14:12; Ezekiel 28:14; or Revelation 12:7, I challenge you to read those passages in the context of their entire chapters and see if you can, in good conscience, still apply those passages to a fallen angel.
If you do wish to continue the conversation, I will show you a passage that proves conclusively that the "devil" of the Bible cannot be a fallen angel. There is indeed a devil but he is no fallen angel. He is, rather, us in all our weakness and proneness to sin. It is no wonder Paul declared with such passion at the end of Romans 7:
Romans 7:19-25 For the good that I would I do not: but the evil which I would not, that I do. Now if I do that I would not, it is no more I that do it, but sin that dwelleth in me. I find then a law, that, when I would do good, evil is present with me. For I delight in the law of God after the inward man: But I see another law in my members, warring against the law of my mind, and bringing me into captivity to the law of sin which is in my members. O wretched man that I am! who shall deliver me from the body of this death? I thank God through Jesus Christ our Lord....
I look forward to hearing from you soon!
I hope you have found this helpful.