This conversation reminded me of an episode of Buffy. To be clear, the portrayal of magic on the show is problematic (along with many other things), but I find it interesting that the writers dabbled in similar principles about good and evil in magic.
In this scenario Willow is a powerful magic user who has become psychotic with rage. (She had attempted to stop using magic because the power was addictive.) Tara has been murdered and Willow found she could not raise her from the dead. (Dawn had formerly tried to raise her recently dead mother but, in a “Monkey Paw” scenario, changed her mind and canceled the attempt before something horrible came from the grave. Warren is Tara’s murderer.
BUFFY: (sighing) We need to find Willow.
XANDER: Yeah, she’s off the wagon big-time. Warren’s a dead man if she finds him.
DAWN: (bitterly) Good.
BUFFY: Dawn, don’t say that.
DAWN: Why not? (the others looking at her) I’d do it myself if I could.
BUFFY: Because you don’t really feel that way.
DAWN: Yes I do. And you should too. He killed Tara, and he nearly killed you. He needs to pay.
XANDER: Out of the mouths of babes.
XANDER: I’m just saying he’s … he’s just as bad as any vampire you’ve sent to dustville.
BUFFY: Being a Slayer doesn’t give me a license to kill. Warren’s human.
DAWN: (scoffs) So?
BUFFY: So the human world has its own rules for dealing with people like him.
XANDER: Yeah, we all know how well those rules work.
BUFFY: Sometimes they do. Sometimes they don’t. We can’t control the universe. If we were supposed to … then the magic wouldn’t change Willow the way it does. And … we’d be able to bring Tara back.
DAWN: (very quietly) And Mom.
BUFFY: There are limits to what we can do. There should be. Willow doesn’t want to believe that. And now she’s messing with forces that want to hurt her. All of us.
via Villains – Transcript Buffy Episode. (emphasis added)
This show, by the way, has multiple moral problems–especially season six in which this episode takes place. But I thought it was worth mentioning.