When she resurrects, does the corpse disappear? It teleports to the altar and returns to life? Otherwise, did she come with a carriage full of clothes and gear, since those would be left behind in the dungeon? If the corpse indeed disappears, Rin will find it disappearing from within itself. Quite an unsatisfactory meal.
If the saint merely loses an arm to a monster, and the monster eats the arm, what happens then when the saint dies much later? Do the atoms/molecules originally in the arm, that are now a part of totally different biological structures, suddenly disappear? It could mean new cells within the monster that ate the arm would suddenly lose parts of themselves, like random stretches of the chromosomes. However, what exactly would mark those atoms as once belonging to the saint? Is every atom covered by magic? If the matter once forming the arm doesn't disappear, will the resurrecting saint henceforth lack an arm? I think not. Maybe there's a separate spell that helps her grow a new one. Or maybe any missing body parts are replaced during the resurrection process from nothing, automatically.
If the corpse needs to disappear for the resurrection to happen, what happens if some magician places it into a magically isolated chamber so that it simply can't disappear? Will the whole body then be replaced at the altar? What if after that the magician resurrects the old body using other (holy) magic? There will be Saint A and Saint B?
So many questions.
Edit: So many typos.