I don't get the meaning of the relationship between the evil king and the magic mirror.

I see it as the evil king is a huge narcissist who likes seeing his own reflection when he fucks someone else, and its also handy to have an obedient slave. And the mirror feels like he has some spiritual/ magical obligation to follow the kings rule. I have a theory that the evil king took someone that was to his liking and cursed them to become the magic mirror and forever serve him.

Having snow white and magic mirror all to himself huh...