>>Though i am curious as to why the Marisa didn't turn on the Reimu for birthing them - i would have thought that would be the kind of thing it'd do. Maybe Reimu is the next in line, there are not enough Yukkuris to kill them quickly. We can think also that Reimu is mentally broken, so there is no need to kill her as the Yurrikus; in this case, the Marisas can abandon her and let it die of starvation, unless she eats the Yurriku, they are filled with bean paste after all.
No, you guys think you understand yukkuris, but you don't in this case. In the mind of a yukkuri why would it kill their loved partner/mother just because some bad yukkuri came out of it? It's the children that are not easy, not the parent.
And I am not knowledgeable about the birth process but can't the father have bad sperm, or in this case bad paste?
It could be that father have bad sperm, or in this case bad paste; however the mother Yukkuri is when crossbreds or mutants are born, because she is not considered by her peers as a normal Yukkuri. And we must remember that Yukkuri Marisas are experts on passing the buck, they will never think that they did something wrong, they blame their parents or mates for their demises in a wink.