I'm sorry, you still think that the royal family married outside of it's blood line before the two current princes? Even Charles and Diana were related, loosely, but still related. No that shit still happens even today, and this manga was not based in this day in age. That's like telling some that writes a historical romance to base it on today's standards when they put in historical facts and customs. That just bullshit.
Ok. Still don't like incest lmao.
I'll give you that. Not a fan, just know it's still a thing even in this day and age, and especially in history. You don't have to like it but if sighing is based in a time when it was historically acceptable, placing today's morals on it is rather moot as it doesn't apply.
*if something is based
I dont like incest irdc if this the story was taken in a old mediviel/ monarchy time setting, where incest was normalized, but this story was written in modern day where its a universal moral opinion that incest is bad like...them being related was not necessary...enjoy yall.