There's a masquerade in this world. The innocuous and gentle magical beings, through superior spellwork and massive trickery, have all the magical beings compelled to hide themselves from the mundanes. And, on top of that, they themselves hide from the rest, who tend to be a brutal and might-makes-right bunch.
But having plopped my heroine in the middle of people who know more of what's going on than she does -- having started to make some little girls babble over dinner -- I realize that they will additionally separate the magical beings. At least by kind. Possibly by more ways. Anything to prevent fighting.
Fighting being the hardest thing to prevent people from noticing.