[Death Regression + Apocalypse + Infinite Flow + EVA-Inspired + Time Reversal + Pure Romance + A Touch of Cthulhu]
…
I was reborn (?), I think, in a future 205 years from now.
Calamity destroyed everything.
A research institute job where I could coast along until the end, in a world full of conflicts and contradictions, but where people could still live in relative peace.
And, most importantly, my home.
There was something even worse, though
There was a calamity living inside me, damn it, constantly waiting to take over my body.
Fortunately, fate gave me a gift:
After I die, I can automatically transmigrate to a new timeline.
…
“Do you think the timelines you abandoned simply vanished? I’ve reaped the consequences they created, every last one of them!”
“But don’t worry. I saved one of them for you. It’ll just cost you something: you.”
Chapters 1-18 are the first copy; Chapters 19-31 are the second copy; Chapters 31-48 are the final copy; Chapters 49-50 are transitional chapters; Chapter 51 begins, entering the fourth copy. Beginning in Chapter 51, the guinea pig became the experimenter.