Its kinda dark, philosophical, nihilistic and even the slightest bit wholesome in a way.
It just the idea of the endless cycle of destruction and rebirth.
Where they have no control over what is going on; other than their souls bing intertwined.
This is shown by the two characters at the end kind of mimicking the actions seen at the start of the manga.
However in a very distorted way, more over this can also be seen with that Male character saying that random girls name.
He is at that moment having flash back from his past lives and is remembering the name (Shuru) which is presumably of one of the Haru's past incarnations.
Thanks everyone at
Speedstar Scanlation for working so hard on translating this series.