First of all,satan was and angel unlike Adam who was fully human but both were given free will to choose good or evil.
Second,God cannot will evil or it would be imperfection and error on His part.
Kosta is right ,Dear Sister.Your view of God is zeus like
Here is some more Aquinas to help you understand
That God cannot will Evil
EVERY act of God is an act of virtue, since His virtue is His essence (Chap. XCII).
2. The will cannot will evil except by some error coming to be in the reason, at least in the matter of the particular choice there and then made. For as the object of the will is good, apprehended as such, the will cannot tend to evil unless evil be somehow proposed to it as good; and that cannot be without error.* But in the divine cognition there can be no error (Chap. LXI). 3. God is the sovereign good, admitting no intermixture of evil (Chap. LXI). 4. Evil cannot befall the will except by its being turned away from its end. But the divine will cannot be turned away from its end, being unable to will except by willing itself (Chap. LXXV). It cannot therefore will evil; and thus free will in it is naturally established in good. This is the meaning of the texts: God is faithful and without iniquity (Deut. xxxii, 4); Thine eyes are clean, O Lord, and thou canst not look upon iniquity (Hab. i, 13).
Chap. XCII link
http://www2.nd.edu/Departments/Maritain/etext/gc1_92.htm
Chap. LXI link
http://www2.nd.edu/Departments/Maritain/etext/gc1_61.htm
Chap. LXXV link
http://www2.nd.edu/Departments/Maritain/etext/gc1_75.htm
Amen, SFA. That is the essential part of the teaching of the One Holy Catholic and Apostolic Church, believed, taught and proclaimed everywhere and awlays. God is Virtue, and virtue is not evil. And God is unchanging.