Marisa went to save the Reimu who's abducted by Remirya just after Marisa proposed Reimu.
Their clan consist of city stray who managed to survive an extermination and finally find an easy place in the forest. Previously, just because a yukkuri hurt human's pet, the whole clan is exterminated, that's why nobody can help Marisa after knowing that Remirya is human's pet.
Marisa decided to go alone. Inside the human's house, he found a lot of transparent box filled with black soil and baby Remirya eating the soil.
He finally found Reimu in an uneasy state. Marisa decided to love Reimu and live with her. Even when Reimu is raped and pregnant with Remirya's babies, Marisa will raise them as her children because Reimu refuses to kill the babies. If the clan refuse them, they will go and find their own easy place.
But all is lost. The babies are about to be born, but this is far different from when Marisa watch her little sister being born.
Baby Remirya eat Reimu from inside and burst open her body.
The human saw everything because Marisa is noisy. He decided to explain to Marisa what happened. Yukkuri's "Why!?" is not a question or demand for explanation, it's just a cry. But the man is bored, so he will tell Marisa anyway.
Demand of predator yukkuri is high, that's why predator plants like this need to fulfil the demand. Predator yukkuri are made the same as any other yukkuri, by refreshing.
The man shake a Fran and let it to Marisa. Fran stabs Marisa with her fang and then licked her wound. After tasting, Fran starts raping Marisa and then go to sleep.
In one or two hours, the babies will be born. Unlike normal types, predators doesn't do refreshing by love. Their mother is nothing more than food, and that's why the father will hurt their partner so her paste tasted better.
For unknown reason, Remirya prefers Reimu while Fran prefers Marisa.
Marisa should start praying. 90% chance the children will be predator, but if miracle happens and all the babies are Marisa.
Marisa kept praying and begging for her babies to be Marisa. From her belly, the babies can be heard. "U~~ U~~"