What's with the light and dark thingy, I still don't really understand a single thing about the King's reason to do this except he's just being extremely homophobic and don't want his daughter marry another woman lol
I think he is more of a generalized bigot. The fact that his daughter chose a woman to marry is not so a problem for him as a piece of evidence that the "witch" has been seducing his daughter with her "darkness". It's not just that it is against heteronormativity, it is also a form of miscegenation, since light and dark magic is something you are born with, like the color of your skin. So yeah, not (just) a homophobe, a bigot all around.