1st Hanada is staying in the future after the accident. She can’t go back to the past because she been missing for 10 years. If she can go back, then there should be 2 Hanada at that time and there shouldn’t be missing report of her. Since there’s only 1 Hanada, she just stay there at that time. Also the age gap between her and Mc decreased significantly, it’s 11 years differences, so it’s barely ok.
It’s also applies to Yuu, since there’s 2 Yuu at that time, the older ones need to be gone.
2nd chapter 29.5 in mangadex is april fools.
