I'm not a christian, but I grew up in a Baptist household, so I have at least a passing understanding of the Bible. Lemme know if I got any wrong.
If I'm understanding the bible correctly;
God Created heaven and Earth, Including Mankind and Angels
God is all-knowing and all-powerful
Relevant to this discussion, God created Lucifer and all the angels who sided with him.
God made Man in His image, and ordered the angels to serve them.
Lucifer, prideful of his own beauty, and envious of God's (at least perceived) favoritism of Man, and of God's position, started a rebellion in heaven and was/will be cast down into the lake of fire(aka Hell).
lucifer later tempted/took the form of the Serpent in the Garden of Eden and tempted Eve to eat of the Tree of Knowledge.
my conclusion: God, with full knowledge of what lucifer would do/become created him and set him on the path that led to his downfall, and to the Sin of Mankind.
Or to put it more simply; God created Sin through his foreknowledge of what Lucifer would become.
I'm not trying to start a shitstorm here, but this is the logical conclusion that I find myself at.
Any Christian pedes wanna poke holes in this for me?
I don't know of any verses indicating that angels are ordered to serve us.
We don't know if these were Satan's motives, a lot of that stuff is just conjecture. All we know is that he thought he could be like the Most High (Isaiah 14:14).
God knew what Satan and later Adam would do, but that doesn't mean that He set them on their respective paths. Foreknowledge of what you're going to do doesn't mean anything's forcing you to make that choice. Foreknowledge is just a side effect of God existing outside of space and time.
God created both angels and man with free will. He gives us the choice to serve Him or not because He wants us to love Him. You can't truly love Him if you're a robot predestined to do what you will do. Creating us with free will also created the potential for sin, but did not guarantee sin itself.
Sin and evil aren't even really things by themselves. They are the absence of God's goodness just as darkness is the absence of light.
Hope this helps.