I don't agree with oversimplifying the meaning of dark storytelling. Either a story has a plot or it doesnt. In my mind there isnt such thing as pure evil. So every antagonist in a story has a reason for doing the things they do. Not saying their choices are the correct ones but they always have a twisted motivation or they are led to believe that the bad deeds they are doing are not actually bad. If the villian is truly twisted then you'd have to agree that they are not normal or have a psycological issue for their reasoning. (which I wont go into... Religion, madness....etc.
KQ in my opinion isnt supposed to be looked at in this way for me. Its a lighthearted adventure fantasy... classic good vs. not good. Theres witches, wizards, talking owls, even death himself. What I think is lost in our current state is that storytellers are trying to make these types of storys or games more realistic. Trying to attach emotional feelings and modern reactions to a genre that is purely meant to stay in the fantasy realm. Yes it may have dark elements but that's just a storytelling arc and nothing more to me.