Looking for a fantasy novel from the late 80s or 90s

Question

I have been searching high and low for this book based on what I remember about it. I remember reading it as a kid so that would have been around the late 90s but may have been published earlier because I got a lot of my books from second-hand stores.

I believe the antagonist is a young adult male who is kicked out of school for breaking into a forbidden library. The once scene I remember clearly is that he is standing on a hill looking down at a valley before descending into it and conquering it using demons as his weapon.

I think the protagonist is a young woman who wasn't formally trained with magic but may have natural aptitude for it, and the book has something to do with the wind. I believe it also had a green jacket with a creature's face on it... I know it's not a lot to go on so thanks in advance.

Books I already tried:

Name of the Wind - published to late to be the right one

Wizard of the Winds - the book I am looking for is definitely European flavor, not middle east.

Answer 1

The book I was looking for is Wind in the Stone by Andre Norton.

Once the Wind united the Valley with the Forest, enveloping them in the strongest of magics which protected the land and banished the threatening Darkness. And there was peace for many centuries...Until the Dark returned.A mage, seeking to enslave the Valley and destroy the Forest, has brutally sundered a family. A mother has fled into the woods with her infant girl-child, while the depraved sorcerer holds the babe's twin--a boy--captive in a black tower. The mother dies but the girl survives. Adopted by the strange denizens of the Forest--safe from the mage's malevolent influence--she grows to young womanhood, cultivating a cherished skill that has been denied the others of her kind: the ability to truly hear the sounds of her world. But her future will be fraught with trial and terror, for only she can smash the chains that shackle the Balley and its inhabitants. It is her destiny to confront sorcerer and demon minions, and to oppose the one she must conquer and free: the magician's protege and her most powerful adversary. Her bane and blood. Her brother.