What I don't understand...(spoiler s)

They were all going to a "family reunion". Did Karen and her boyfriend/cousin know that they were not really related? Seems to me that all that family history was new to them, so I think it was pretty gross that they were also lovers. And why did the movie need this? Was it really crucial to the plot? I don't think so.

It's also never really explained why Karen, this doctor, often has sudden cramps/pain and she takes some mysterious substance to ease it instantly. I get that it must have had something to do with getting her pregnant, as this was referred to, but I really don't understand how. Besides, I think they are really taking a leap of faith, hoping that she gets pregnant after only a few brief minutes in the tub!

I also don't get why she is changed at the end. I knew something was going to happen, because they said the host would kill the last warrior, but it was such a sudden change that I think needed to be explained, or drawn out.

And where does this "inheritance" title come from? The fact that they "inherit" riches and the right to kill their children? I think maybe "Family Reunion" could have been a better title. I also started watching this movie, not knowing anything about the story, thinking that these family members were going to go through trials to see who would actually inherit everything. I think that would have been a better movie!