Morgana may be considered dark, or evil, but we all know that it’s because she was misunderstood, and a product of her time. I don’t know if that’s true but the thing is, if you’re a brooding mage, are you going to be all cheery posies all the time?
No, you’ll probably have a dark streak! But deep down, you’ve got some light and goodness.
Anyway, the thing is that it’s hard to find a good, female mage or sorcerer. I’m not sure what that says about females and inborn magic and our culture, but it definitely says something!