How much a real female is Rein? Does she actually have a vag00? If I injected sperm in her vag00 would she get pregnant? Would it kill her? Or would she have a Rein sized kid?
how is babby formed?
These are bad questions and you are a bad person for asking them.
You are a bad OP. You should be ashamed.
She's made of magic.
Since we know she can change her form of that to a regular size human, I imagine she can manipulate herself easily to be fully functional, at least cosmetically.