According to the YouTube comments on the video of Sankarea ep. 7 that I watched, it’s legal for cousins to marry in Japan, which clears up some of my confusion with how ethical this episode is.
(By the way, a user on YouTube has uploaded all the aired Sankarea episodes in HD, so go watch them before YouTube catches on! Go go go!)
It’s kinda nice that we got a little Chihiro x Ranko backstory. After the last episode, I was pretty curious about what’s going to happen next, since everything up until now has basically been us watching the characters come to the same conclusion that we already figured out, like how Rea needs to eat the poisoned leaves. Chihiro’s gramps is obviously a zombie since he eats them all the time too, so we do still need to wait for Chihiro to catch on to that, but otherwise there’s not too many clues on where the plot is heading, so you could say we’ve reached a turning point in the plot, going into the unknown, and the Chihiro x Ranko backstory is a nice break from the Rea stuff.
If only they weren’t cousins, and Ranko wasn’t exploited as such a fanservice character, I would think this pairing is really cute.