Worst character? (cast your vote)

CNagy said:

No, that's not how it gets done. Whether by the Westermark effect or by gradual awareness of social taboos, it is a process that happens over a period of time. What Manami did was screw up Kirino's development and she bears a lot of the blame for any incestuous feelings between the siblings.

Generally speaking, children with kinder older siblings tend to idolize them. This is non-sexual, because those children have not sexually developed. They have no real idea of what "marrying" their older sibling or their parents entails.

Here's the situation if Manami were hit by a truck before she could influence Kyousuke: Kyousuke continues to overachieve. People are under this impression that he was actually an average guy, but the evidence of the episode is completely to the contrary--always getting first place, grades at the top of the class, teaching Manami, and even Kyousuke's eventual A-grade on the present day exam show Kyousuke is exceptional when he applies himself.

So Kyousuke continues to overachieve, Kirino chases behind him. In a direct comparison, he would always be ahead of her simply due to his age and their similar efforts. He'd be smarter because he'd have more years of studying and schooling, he'd be faster because he'd be taller and more developed, etc. And in this scenario, the same thing that happens to practically every other opposite-sex set of siblings would happen; in time Kirino would develop a sexual attraction instinct that did not include Kyousuke as a potential mate.

Now instead, let's look at what Manami did; she essentially stunted Kirino's feelings for "exceptional Kyousuke" at the level of childhood idolization. Even more, Kirino disassociated "lazy Kyousuke" from "exceptional Kyousuke" and worked hard to ensure that she was someone "exceptional Kyousuke" would be proud of when he returned. And when some element of "exceptional Kyousuke" does show up years later (specifically, the aspect of Kyousuke's where he always protected her/solved her problems as a child), some of that idolization returns--only now Kirino is not an undeveloped child, she is a sexually developed young woman.

To put it very simply: Manami mindfucked an impressionable child in a completely normal stage of development. She also brought an exceptional Kyousuke down to the level where she could exert some control over him. She was, essentially, instrumental to this whole incest ending.