It's so cartoonish it retroactively harms the prior relationship the main couple has, it's actually impressive that it could do that. They just needed to keep it more vague, or not have a paper thin cartoon villain that even if he did have further motivations has no time whatsoever to expand on them.
The witch didn't even get to express anything other than I died immediately after you did, I thought there would be her living for a while after and actually seeing how meaningless life is without him but she goes after him immediately. It's so strange.