- Biyori seems to take place in the present day. Perhaps Hinamizawa was renamed to Asahigaoka after its spate of, ahem, bad publicity.
- Alternatively Asahigaoka is the Mirror Universe equivalent of Hinamizawa. Instead of making people crazy and evil, it makes them honest and kind. Nobody needs locks on their doors!
- The second season, Repeat seems to be an Inter Quel. But using Insane Troll Logic, it could possibly be a "Groundhog Day" Loop as well...
- It's Suguru, explaining his inability of speech. He choked on a rice cracker one day and Natsumi, unable to bear the loss of her beloved onii-chan, performed a satanic ritual to get him back. She may have had to sacrifice her intelligence to do so.
- She did sacrifice her drive to do stuff instead. She's not dumb, but lazy as fuck. Before that, she was very studious, so this sacrifice will let her brother live for an unnaturally long time.
- It may also have been the few more-or-less successful human transformations ever. She sacrificed her very strong drive and got her brother back minus his ability to talk.
- Or even worse, she (yes) made a contract with Kyubey. Coincidentally, in keeping with WMG tradition of "this character from Show X is related to this character from Show Y", the Koshigayas are related to Kyoko Sakura's family. (Just because one branch of the family converted to Christianity doesn't mean the whole extended family would.)
Kazuho must how somehow gotten pregnant during her final year of high school, and since she's already out of town for school, no one in town would have noticed (except for Hikage and the Miyauchi 'parents'). The Miyauchi 'mother' could have simply pretended to be pregnant until Renge was born.
Kazuho's depression (as evidenced by her oversleeping), lack of appearances (although mentioned) during flashbacks, and sharing the same futon at home as Renge points to this.
- Fun Fact: Ted Bundy started out the same way (his "big sister" was actually his mother).
There may have been a limnic volcanic eruption from a nearby lake that flooded their town (seemingly located in a valley) with deadly carbon dioxide gas and suffocated them. Meanwhile Suguru was elsewhere, perhaps for his high school entrance exams. When he returned home he went mad from the revelation and stayed in his old house, insisting that his family and friends were actually still alive and would soon return. To this day he squats in his former house, occasionally riding into a nearby town to steal food.
The reason he seems to be silent is that we of course see the show from the ghosts' POV, and just as we mortals supposedly only catch faint glimpses of ghosts, they have limited ability to contact us.
- That soldier was her grandfather, an American Marine who briefly served in Japan, where he had a whirlwind romance with her grandmother before shipping out to Vietnam.