From what I understand, it doesn’t need to be Musica’s blood specifically, but the blood of anyone with the ‘curse’.
So currently, one cup of blood from Sonju and Musica = 2 more cured demons. Wait for Sonju and Musica to regenerate blood = 4 more cured demons.
The process would be slow, but the turning would need to be either extremely slow or extremely quick to prevent the royalty demons from finding out and repeating the past.
well sonju would never give his blood, he wants to eat human flesh again, I don't know why he stays with Musicaa desiring for the promise to break and chase cattle children, maybe Musicaa is a really badass final boss I dispite being so cute, but I would not trust sonju on that, a cup of blood still looks a lot for her height and weight, if we think that they are more than a million of demons, that would take quite a time
The thing is, that Emma as smart as she is, is only a child even though everything happened. It's the same as in Shiki. They eat to maintain a humanoid form and somehow survive, we kill animals, pick vegetables, to stay alive. The world that Emma wishes for can only stay a dream, because like it was said, not everyone thinks like her, or like musicaa, the cattle children's life are at stake's. And they won't be able to go into the human world and be accepted, they will be killed to maintain the order of the first promiae. I am not for the extinction of the demon race. But, like in Kiseijuu (Parasyte on Netflix), Norman wants to stay alive and protect hia family, so what's wrong with that ? But what is also wrong about eating human beings ? I don't know why they so badly want to keep their humanoid forms by eating cattle children, and why they reject and fear so badly their original form. If we knew, maybe we could think again. But now, bleeding out that poor Musicaa just to avoid demons to eat humans seems pretty cruel to me. There are so many demons..., she's so little and tiny, it could kill her. And as Norman said, it would not stop them to eat cattle children. I know you as smart, brilliant and nice girl Emma, but at some point, you just have to stop and face it, your options are limited. And the others shouldn't have to pay the price for your guilty conscience about those who don't regret eating Conny and hurting Phil... I'm not saying to forgive and hate. But to be pragmatical and smart. Cohabitation ? It won't happened, and if it does, somehow war will wage, again.