Can wolves become sheep, or tares become wheat through their will or effort? I doubt it. It is not God who sows tares into a field of wheat, but Monsanto, the evil one.I think we need to be careful when we label people "evil." We can name behaviors, even beliefs, "evil," but that doesn't mean the person who does them or thinks them is evil.
All people are children of God, part of God's creation.
The most vile person I can think of is Hitler. He did evil things. Did God make him evil? If not, then did God not make him? If God made him good, then he is not evil. He is a child of God who did evil things by his own free will.