I don't see any real big problem. assuming each return to the past create a new separate timeline (which is the easiest to avoid all the paradoxes) :
Timeline 1 : kako live by herself, dont know mirai, is a genius scientist. Mirai use kako genes to create nozomi and go back to the past to marry her.
Timeline 2 : kako and mirai marry and live together. a one point they split. "kissa" return to the past because she became immortal
Timeline 3 : (current) "kissa" warn kako about the immortality. she decide not to do it and live together with mirai happily ever after.
Michi ? who's michi ? :D
last edited at Jul 15, 2026 4:05AM