i’d forgotten that lucretia’s shield spell is essentially a souped-up version of “shield of faith,” which is a cleric spell that merle teaches her during the stolen century.
clerics and paladins get their powers from their faith/devotion, but during the third lunar interlude lucretia says she doesn’t really have faith in anything. to which merle responds, “you have got faith: it’s faith in you”
basically lucretia believed in herself so hard that she gave herself god-like strength and cast the most powerful spell in history