Actually it's not incest at all. In Japan you can marry your cousin because they are considered extended family and not immediate family like it would be in the USA.
Brasil also see cousins as extended family. And it's still incest, since the couple in question would be related.
Japan is Japan and Brazil is Brazil. In Japan incest is no big deal. It really just depends on a country's views of social issues. Was just giving a fact. Sorry if this comment or the previous one offended you. (●'◡'●)ﾉ
Cousins in the US are considered extended family but still within the off limits range. Immediate would be parents and siblings.
I loved chapters 1 and 3, enven though the third story was sort of incestuous