Responses
Its because these aliens have life that stretches so long, that Mori's human lifespan is just that short. 200 years is nothing for these aliens. It's to drive the point of just how different these two species are, and is Miria still willing to be the mother, despite knowing all of these. Is she able to go through being a mother, knowing that one day she will have to witness Mori dying. Unlike her who will continue living forever. I think its beautiful in a way.
They don’t need to keep mentioning that Mori’s life will eventually come to an end. He’s still a baby and that other human ended up living for like 200 years I think. So this manga better not end with a flash forward to Mori being old on his deathbed. If anything I’d like to see teen Mori or adult Mori. Or Mori searching for more info on his background and biological parents.