There is a series of books called "Wicked" . They are the story of OZ , from the point of view of the  wicked  witch of the west. Her name was Elfaba. She was a "good guy". She and the good witch of the North were room mates in collage.Best friends.

Above you can see the two of them. Galinda the good witch, has the blond hair.

you can read these books (4 of them). Google "Wicked series"