Karen really did open up with Sayaka that fast, I thought she would be more of those jealous type of girl.
Stepsister? Where else have seen that before?
That so old.
But protagonist is might not be too good . It could get scary.
dude, not even having the INT stats maxed out will you ever get to understand wtf happened during those 5 mins you left the room... also they are cousins huh...okay lil sis im rooting for ya!!
Science says it's ok to marry your (first) cousin. It's almost no risk at all to your children (the risk is only slightly increased, equal to having child at age of ~35, i.e. still very low) (though marriage between first cousin over and over for several generations consecutively will make genetic diversity in your family line suffer). More distant relative? The better.
Religion? IIRC from major religion in this world, Bible and Qoran allow it.
And I 'think' polygamy is acceptable AS LONG AS each party agrees.
It's widely practiced for a long time, the kid's parents would be clear (kid's father and mother can be distinguished from each other).
Religion? Again, Bible and Qoran allow it (though I read it somewhere either Bible or Qoran limit it to max 4).
Allowed =/= had to do it
It's still bound to each person's free will to do it or not.