I think that's actually supposed to be strawberry guts, not blood. There's anothe image of this white mage by this artist with her holding a giant strawberry.
Seeing as Marriage of Figaro is a completely unofficial and non-canon doujinshi, "who is Prieur Francesca?" is a perfectly valid question. She has no official name, and is only referred to as Matron/High Priestess in the game. She shouldn't even be on the tag list as a character, just as something like "old woman" if you really want to tag her at all.
