Considering you are at least a bit open minded and able to see yourself in someone's else position, you shall enjoy Koi Kaze. Incest is for sure a taboo in society, but the realistic and mature way KK approaches it makes you completely forget about it and ask yourself "what is the problem? they didnt decide to love it each other, it just happened, why should they deny their feelings?".
The plot goes around these 2 brothers who grew apart from each other, have a nearly romantic meeting and start to develop mutual feelings, when they suddenly find out to be sibblings. We then watch the drama of their internal struggle, to bury these newborn feelings and see each other as regular brother and sister. But as we all know or eventually will, no one can control the heart to that extent. Between being harsh or mean to each other, trying to abide to personal or social values, their love always find a way to flourish.
Koshiro plays mature part of the dilemma. He fully understands how loving and having sexual desire for his sister is wrong and is deeply tormented by that. He tries to bash the poor girl away in a attempt to not only make her hate him, but also to bury his own feelings. He even moved out of their house in a desperate way to cut all ties before he couldnt restrain himself anymore, while going down the path of depression. He knew it was wrong to have to those feelings, but denying those was killing him.
Nanoka plays the innocent and pure part. Initially trying to be the cutest sister possible, she later realizes her true feelings. Unlike her brother, she doesnt run away; besides knowing those wouldnt be socially accepted, she takes the "why is it wrong?" stance. Not even Koshiro's attempts to make her hate him made she wave. And thats exaclty her pure hearted love and determination that wins not only her brother's, but also the readers' hearts.
With all that else, its implied that the story, the characters and their developments are the shinning jews of the story. The art style is simple, more going towards the realistic style. Voice acting was awesome, to say the least. OP and Ed musics are cool, but there are no BG music that stands out. Maybe because its such a taboo theme, the anime probably didnt receive much funds which resulted in poor animation most of times.
If you were able to break away from society predefined moral rules and enjoied this master piece love story, I recomend you read the manga starting from chapter 27. There are a few subtle changes from the anime that you wont want to miss.
