"Miserable? That's not for you to decide." - Koshiro

While many anime toy with the idea of being attracted to a sibling thanks to the popularity of the "cute little sister" archetype, none of them take it seriously. Think, or really any harem where there is a little sister character who displays abnormal amounts of affection towards the main character. The archetype is played for cheap humor and fanservice, only eliciting eyerolls and feelings of disgust from the viewer. It's only natural, we all know incest is wrong- that's why anime never takes it seriously. Cue, a show which seeks to challenge our perception of the taboo.To be clear, the show does not support or condone incest. It does not skirt around the issue either by playing the "they're not blood related" card. For most of the story, Koshiro feels ashamed that he is in love with his sister, to the extent of self loathing. His work supervisor Chidori also acts a voice of reason at the end of the story when she finds out about his relationship, stating that they will be judged by society and end up living miserable lives. The ending even foreshadows their relationship not lasting- the tree that the lovers carve their names on will be cut down.Koi Kaze challenges the taboo of incest by crafting a romance that we the viewers care about. The connection between Koshiro and Nanoka is not formed from physical attraction- instead it is emotional. Both characters expose themselves emotionally when they reveal that they were both dumped by the person they were dating. Being in the same situation, they mutually console each other about it and end up feeling better. Indeed, Koshiro does not love Nanoka because she is pretty. Koshiro's coworker Odagiri is meant to emphasize that- his fetishization of highschool girls and little sisters shows he is only attracted to them superficially, contrasting with Koshiro's emotional connection with Nanoka. Sexual attraction between Koshiro and Nanoka is only a result of their emotional attraction.From the first episode, Koshiro is set up to be a sympathetic character. His life is that of tragic irony. He works in a marriage arranging company, but he himself cannot find anyone he truly loves. His ex girlfriend even questions whether he has ever loved anyone. The moment he does find someone he truly loves, it's a love that he cannot have. He's knows that its wrong, and he really struggles with it. We can empathize with him in that regard. We have all struggled with feelings that we can't suppress, even though they may be wrong. He cries, he self loathes, he distances himself from the cause of these feelings. But sometimes he can't help it. Sometimes we can't help it. How wrong it may be, we find ourselves kinda rooting for him- we want him to stop hurting and just be happy.While Nanoka does not struggle with as much internal turmoil as Koshiro, we may end up thinking of her as young and immature, not understanding the implications of such a relationship or whether she really loves her brother in a romantic sense. But we see that she does. She is exposed to love and romance at school. She does know what romantic love is. Towards the end of the show Nanoka affirms that her love for Koshiro is as strong as the romantic love Chihiro claims to have towards him. She too is someone we end up rooting for.The ending of the show is ambiguous, possibly even foreboding- the tree the lovers carve their names on is bound to be cut down. Maybe society will pull their relationship apart in the end. But that's not what is important. The tone of the final episode itself is one of hope. The characters aren't concerned with how society treats them. In episode twelve, Koshiro scolds Chihiro that she doesn't know how his life with Nanoka will turn out. In the final episode, the lovers decide that being alive and suffering together is better than to commit double suicide. Koshiro's final line of dialogue reaffirms that he loves Nanoka- that's all that matters. It is very clear that even though they are siblings, these characters are deeply in love. And if they are, who are we to object?Koi Kaze never gives us an answer to the incest taboo. Itdoes not touch on the results of genetic inbreeding, what I perceive to be the biggest objection to incest and the reason why I still cannot support it. But put that aside, I've realized that what remains is a gut feeling of wrongness. "Incest is weird, it's not natural." This feeling has been coded into our being, for evolutionary purposes of course. However, by crafting characters we can root for and a moving romance, that feeling has eroded away. That is the beauty of Koi Kaze.