“Free will.”
Did God give Angels or the Devil Free Will?
Every living thing, including trees, etc, have ‘free will’. If you believe Angels and devils are alive then they too have ‘free will’. And don’t make the mistake of thinking insticnts cancel free will ... raccoon mommas can disprove that one real quickly.
http://www.newadvent.org/cathen/04764a.htm
“Diabolus enim et alii dæmones a Deo quidem naturâ creati sunt boni, sed ipsi per se facti sunt mali.” (”the Devil and the other demons were created by God good in their nature but they by themselves have made themselves evil.”)