God doesn't give in the Bible "Black magic is bad, but if you use magic for Me, it is alright". He didn't say "Suffer not a witch of Satan to live, but a Christian witch can live.". He said "Suffer not a witch to live". Any magic in this world is not of God, but of the devil.
I've never read Narnia, and 1) I have been told not to, and 2) I have no desire to.
I've not read Tolkein either, but I have a feeling its another one my parents wouldn't let me read.