Honestly disappointing that the author is doing this. I could kinda understand before with all the twists as they try to recover Nana, even though that was getting tedious, but now we're hit with yet ANOTHER twist, with a potential amnesia arc just starting. Like sure, it makes historical sense with the earthquake and all, but the jumping around is making me lose the great enthusiasm I had before for this series.
I didn't read the spoiler above, but all I can hope for is that this doesn't take too long and we can have a happy ending, which both Kazunari and Nana deserve.