Hi Casi,
This is my third attempt to answer your post. It's an excellent question and it deserves a quality answer. But I'm afraid to write another quality answer after what happened to the previous two.
My beliefs fit more or less within the loose framework that is Wicca, but I don't call myself Wiccan. It's a niggle, but it's an important niggle to me
I'm a dualist, a pantheist and a polytheist and these "ists" color my beliefs regarding the origin of evil.
As a dualist, I believe that the Divine is both male and female. Also, as a dualist but wearing a different dualism hat, I believe that the Divine, as well as everyone and everything in our universe is both dark and light. Or good and evil in our human, mortal, limited lexicon. Harsh winters, violent storms and natural disasters may do great harm but often the same processes also do great good as well. And often human choices about where to build and where to live and how to build turn a bad storm into a disaster. Think: Florida, high density retirement communities and mobile home parks, limited highway infrastructure to move large numbers inland, and the tendency for people to postpone evacuation until the storm is upon them and they fully understand the forces involved. Do Floridians deserve to suffer losses in hurricanes? No. Is there a certain inevitability given the nature of storms and the choices that people make? Yes. That's a bit of a digression, but possibly illustrative of the basic neutrality of natural forces. Death is a natural and necessary part of life. From death comes renewal.
As a pantheist, I believe that the Divine dwells in every creature, every mountain, every river, every tree, every grain of sand and every speck of cosmic dust in this universe. There is a spark of Divine in the landslide, in the earthquake, and in the psychopath. Does the Divine urge the psychopath to commit an atrocity? No. The choice is in our hands to do good and to do evil. Some people choose to hurt others, hurt themselves, hurt the planet. Some people choose to act unmindfully with sad results. When our grasp extends further, I am sure we'll do harm to other planets as well.
As a polytheist, I believe that the avatars that humans worship are real and tangible. These Old Ones, these Gods, Goddesses partake in great measure the nature of the all-encompassing Divine. But, I don't believe in the personification of Evil. Dark and light intermixed and inseparable, but not Dark alone, not an Evil One. Humans have no need of a great Temptor. En mass, we do a fine job of tempting ourselves, of resisting temptation, and of succumbing to temptation.
I hope clicking the post reply button will not cause an abrupt reboot this time!