There is a pretty common phase about love and hate, that has to do with there being a fine line between them. And there is a lot of legitimacy coming for the saying simply because both emotions are strongly influenced by one particular person; not only that, but that person gets the attention of you also to the point of obsession. Whether you want to strangle their neck or kiss it, those feelings are pretty much coming from the fact that you have this intense fascination for someone; depending on where that fascination is fueled by hate or love, will influenced what body part you wish to use on said neck.
Probably the most interesting use of these extreme emotions this season is Toaru Hikuushi e no Koiuta. Knowing the deep hatred that Kal-El has for Nina Viento -- which was reveal right from the first episode -- there was some amount of certainty that they would meet up eventually in the story; and with the more recent reveal, this is what made for a bigger surprise than anything. Not only did we know about Kal-El's thirst for revenge, we also saw the beginnings of a romantic relationship between him and Claire Cruz. The wonderful twist is that the one he is beginning to love, is the one he hates the most to his core; and this whole dynamic is something that really is a fascinating hint at what is to come in this series.
When first going into Toaru Hikuushi e no Koiuta, I kind of expected this to be much more of a Romeo and Juliet type of story simply because of the fact that Kal-El and Claire were split in "factions" based on economic status -- that being poor and rich, respectively. Luckily there was a bit more complexity to the relationship of these two teenagers, and Kal-El isn't really of a poor family because he used to be Karl La Hire and got brought into the Albus family after loosing everything thanks to Nina Viento and her movement, the Revolution of the Wind.
Knowing that Claire Cruz is in fact Nina Viento, I'm interested in seeing what the big reveal to Kal-El will be, or will Claire remain silent as they slowly grow further and further apart. If anything, I'm putting my money of the former seeing as Kal-El stitched back up that initial push for distance, coming from Claire, after she figured out he was Karl La Hire on her own. Although, that was probably the lamest and most cliché phases Kal-El spout to Claire; it is used by many anime characters, basically is dumbed down to "You are you" type of phases, which isn't deep in the slightest.
Either way, with the fact that Kal-El still hates Nina Viento -- Claire's alternate persona -- there is a possibility that he will be over whelmed by hatred and do something he would regret doing after his hatred subsides. Or, he could forgive her actions because love conquers all -- at least in the context of a majority of anime. There is no doubt that this conflict of extreme emotions will be a good character building moment for both Kal-El and Claire, simply because it does seem like Claire regrets what happened to Kal-El's real parents. Really, I feel a bit diabolical for hoping that this ends on the bad side of things, but more than likely it will be the love conquers all approach.
So for something that seemed like another Romeo and Juliet love story, there is some interesting pieces in this anime that make it very unique. I would be surprised if Toaru Hikuushi e no Koiuta goes that hatred route, or better yet, something I haven't even thought of. Really I'm excited to have a romance that isn't always based in a normal high school setting, and just want to see where Kal-El's emotions will lead him with the enviable reveal of Nina Viento's true identity.