So... do the dudettes know/remember he killed them, betrayed humanity and destroyed the world?
Because, if they do, the vibes are completely off.
It should be a story about tragedy, what's right, how much are you willing to sacrifice, trauma..
I don't get the plot. He killed everyone he cared about, in order to kill demon lord by sacrificing himself and by doing that he regressed. I mean, what is the point of going back in time if mc will have to live his life knowing he will have to face that demon lord again? It was said he regressed to the past but there was nothing about any changes. So did he do the whole sacrifice thing knowing he would go back in time? What was even the turning point in his life that every relationship with these heroines he killed was beyond saving and he had nothing else to do but regress? And what he would gain from going back? What information or experience would help him to change everything that already happened? If the answer is "the system" then this story will hit me with a great disappointment. The concept is cool but there is little to no explanation of how it essentially works as it's too vague plus it's not really making me excited to see another story where mc is turned into his younger self - a kid, who for whatever reason surprises everyone how suddenly he becomes different in any good way...