The main theme of this manga seems to be recurring suffering. So I was thinking that maybe this is just a manga version of internal recurrence? And it will end with the MC becoming the Übermensch? Probably not, but just an idea. That would be an incredibly unsatisfying ending. For the of you not familiar with the ideas of Nietzsche, watch the video, maybe you'll see what I'm getting at. It's got mega man, so that's cool.
https://www.youtube.com/watch?v=i6esRZLAR1Q