I answered that way because you contrasted "Fallen" with "Very Good" in their origin and destiny:
I like to say (with an eye to Chinese Buddhism) about humankind and creation, "Not good, not bad, both good and bad, neither good nor bad ...but FALLEN -- but in their origin and destiny (as offered, though some will despise it) very good, as God himself said."
I'm certain God had His reasons for creating Satan who tempted Eve in the Garden of Eden. And no doubt it has to do with His justice and therefore, Satan's destiny.
Yet Michael the archangel, when contending with the devil he disputed about the body of Moses, durst not bring against him a railing accusation, but said, The Lord rebuke thee. But these speak evil of those things which they know not: but what they know naturally, as brute beasts, in those things they corrupt themselves. - Jude:9-10
Bottom line, this present Creation is infused with duality as betty boop says - including good/evil (which brings us back to aruanan's point about Manichaean duality.) The new heaven and earth, the "Final Cause," will have none of the evil:
And I saw a new heaven and a new earth: for the first heaven and the first earth were passed away; and there was no more sea. And I John saw the holy city, new Jerusalem, coming down from God out of heaven, prepared as a bride adorned for her husband. And I heard a great voice out of heaven saying, Behold, the tabernacle of God [is] with men, and he will dwell with them, and they shall be his people, and God himself shall be with them, [and be] their God. And God shall wipe away all tears from their eyes; and there shall be no more death, neither sorrow, nor crying, neither shall there be any more pain: for the former things are passed away. And he that sat upon the throne said, Behold, I make all things new. And he said unto me, Write: for these words are true and faithful. And he said unto me, It is done. I am Alpha and Omega, the beginning and the end. I will give unto him that is athirst of the fountain of the water of life freely. He that overcometh shall inherit all things; and I will be his God, and he shall be my son. But the fearful, and unbelieving, and the abominable, and murderers, and whoremongers, and sorcerers, and idolaters, and all liars, shall have their part in the lake which burneth with fire and brimstone: which is the second death. - Rev 21:1-8
Therefore I am certain that all of it - including the present evil - works together for the good according to God's will and timing.
For I reckon that the sufferings of this present time [are] not worthy [to be compared] with the glory which shall be revealed in us. For the earnest expectation of the creature waiteth for the manifestation of the sons of God. For the creature was made subject to vanity, not willingly, but by reason of him who hath subjected [the same] in hope, Because the creature itself also shall be delivered from the bondage of corruption into the glorious liberty of the children of God. For we know that the whole creation groaneth and travaileth in pain together until now. And not only [they], but ourselves also, which have the firstfruits of the Spirit, even we ourselves groan within ourselves, waiting for the adoption, [to wit], the redemption of our body... And we know that all things work together for good to them that love God, to them who are the called according to [his] purpose. For whom he did foreknow, he also did predestinate [to be] conformed to the image of his Son, that he might be the firstborn among many brethren. Moreover whom he did predestinate, them he also called: and whom he called, them he also justified: and whom he justified, them he also glorified. - Romans 8:18-23 and 28-30
God's Name is I AM.