I disagree with that first premise; I don't think evil implies some root causation outside the control of the individual. I view evil as a privation of some good. What is good is perfectly natural, and easy to discern: life, health, well-being, and so on. If any of these things are lacking to the individual, that is an evil, generally speaking. Intentionally bringing about such an act in oneself or another is a moral evil.

I think you may be misunderstanding my position on what exactly evil is. Describing it as a "possessive ether from satan" gives evil a positive existence in its own right, and that's simply not how I conceive of it. Evil is lack. It's not the antithesis to good or holiness, because the antithesis of something is itself a thing. Evil isn't a thing, but instead it is the lack of thingness, or some aspect thereof.