I think if he's evil there's every reason to bring her back. It's the same god that brought one of the Dullahans back because they likely executed someone the god didn't like. So bringing her back also played into his plans but she's just not having any of it. She is directly going against the god himself as well. But you're right. We are going to have to wait to find out.

I Have a feeling the knight is one of the twelve, probably the one who betrayed. So not one of the original 10 sinners. But having had that dream of being faced with either cutting a head or having his head cut, he might end up as one, a new addition to the original sinners, should he betray god and not cut whoever’s head is demanded. Or sum like that, might be why they all feel such an intense dislike for him. More than the knight tho, that second prince need to grab his jezzabelle and fuck right off